Lost Power :( ... please help

[Col]

Hey, I am new to the world of Mustangs, but picked up an automatic GT about 3 months ago. For those of you who are like me and frown upon autos, the car is kind of a gift so I have no choice.

It's a standard 98 GT which has had no mechanical problems since my father-in-law bought it in 1999, but has about 95,000 miles on the clock. I immediately had to replace the coolant... um... manifold thing above the engine, which I added to an oil and coolant change. On return the mechanic told me that the spark plugs were out, so I replaced them with standard champion plugs and also replaced the fuel filter (again, standard off the shelf box). However, since doing this work, the car doesn't accelerate properly. 0-60mph takes about 10 seconds, instead of maybe 7ish before (are these figures right?). My situation is that I only recently moved to Canada from Europe, and am still waiting for my work permit - and running the Mustang is eating enough of my savings without having to factor in a mechanic. For the moment I am hoping to rely on help from this forum until I am able to give the car to Ford and say "get this working well for me please" (or more realistically, "Can I exchange this for a newer standard model...").

My instinctive feeling is that the spark plugs are the problem. They are gapped to .54 and lightly tightened. There are no visual problems with them, and the shop tells me that the plantinum plugs only affect life, not a drastic performance change. The mechanic I spoke to knows little about the Mustang, but tells me that platinum plugs may be needed. Am I going in the right direction by replacing them again? Is there anything else I should consider as a likely cause?

Thanks to anyone who has the time to offer any advice.

 

[ACSPONY]

That spark plug gap sounds right to me, what plugs did you put in?
A search on here looks like Motorcraft AGSF-32C (copper) is a good plug.
http://forums.stangnet.com/showthread.php?t=398960&highlight=spark+plug+gap
http://forums.stangnet.com/showthread.php?t=555472&highlight=spark+plug+gap
~A.C.

 

[RedBullitt]

eh, why frown on autos? they will walk all over a manual if they are built right. not as fun, but they really do handle the power of beasty cars much better. you really shouldnt "need" the platinum plugs, but worn plugs etc could be your problem. maybe your sensors, like maf and o2 could be on the way out as well. go buy some seafoam at autozone and run it through the car <intake, oil and fuel> and that should help too.

 

[sbelyo]

Ditch the plugs that you have and use Autolite 764 plugs. It was the best $9.60 I ever spent. And that was for all 8 plugs. The car ran smooth as silk and acceleration was better than new with 70K mile on the clock. Someone correct me if I'm wrong, double check that all the plug wires are on tight. Sometimes the boots get worn out and the clips don't hold. My 2001 has COP so I don't have any plug wires but I did forget to plug 2 coils back in after a change

Check for my thread on here Plug change a success.

Also replace the air filter and clean the MAF. There is a write up on here somewhere on how to do that.

 

[Col]

I cannot recall the model number, but I used the Champion copper plugs suggested in their book. I tested the leads by taking each one off to ensure that there was a difference when it was connected. These plugs probably have 600km on them, so they are not worn.

<maf and o2 could be on the way out as well> I am guessing that MAF is the airflow meter? Before the the oil and plug change everything was running well, so the change is sudden. I am wondering whether the mechanic has made a mistake piecing everything back together after replacing the coolant manifold above the engine, or whether I might have made a mistake putting the air hoses back on after changing the plugs. There is a sensor after the air filter which may have been banged around a little, what is that for? Since my first post I have been out for a drive, and it's really sluggish - can't even spin the back wheels up when pulling away!

Why do I prefer standard shift? I don't like it when you put the power on coming through a bend and the car decides to shift too late (or changes up too early). I am from England originally and used to fast, windy lanes in the Kent country side - almost killed myself first time I took the Mustang out alone! Yeah I know...

 

[Mike97gt]

I cannot recall the model number, but I used the Champion copper plugs suggested in their book. I tested the leads by taking each one off to ensure that there was a difference when it was connected. These plugs probably have 600km on them, so they are not worn.

<maf and o2 could be on the way out as well> I am guessing that MAF is the airflow meter? Before the the oil and plug change everything was running well, so the change is sudden. I am wondering whether the mechanic has made a mistake piecing everything back together after replacing the coolant manifold above the engine, or whether I might have made a mistake putting the air hoses back on after changing the plugs. There is a sensor after the air filter which may have been banged around a little, what is that for? Since my first post I have been out for a drive, and it's really sluggish - can't even spin the back wheels up when pulling away!

Why do I prefer standard shift? I don't like it when you put the power on coming through a bend and the car decides to shift too late (or changes up too early). I am from England originally and used to fast, windy lanes in the Kent country side - almost killed myself first time I took the Mustang out alone! Yeah I know...

this happend right after the plug change? if so BRING IT BACK TOO DOUBLE CHECK EVERYTHING

i bet your car is misfiring like crazy? does it buck? does it shudder under accel?

we need a lot more info on how it drives now. what rpm range does it fall off.. does it shift 1-2 like it used too?

 

[Col]

Thanks to those who have been able to offer me advice.

this happend right after the plug change? if so BRING IT BACK TOO DOUBLE CHECK EVERYTHING

i bet your car is misfiring like crazy? does it buck? does it shudder under accel?

we need a lot more info on how it drives now. what rpm range does it fall off.. does it shift 1-2 like it used too?

It started happening after the mechanic changed the cooling manifold (I still don't know the name of this part). He told me the plugs were badly worn and the car was misfiring - the car had much slower acceleration when I took it back. I checked the plugs, and he was right about them being useless. Changing them appears to have stopped the car from misfiring, but has not returned power. I am wondering whether the leak on the manifold has caused some problems... the water sprayed over the first two plugs on the passenger side, could it be that it is still in there causing one of the new plugs to fail? Maybe I should re-change those two plugs, but how can I ensure that the sockets are clean (is compressed air enough)? I'll stick with the Champions for now so they match, unless someone tells me that they are a problem.

There is no shuddering, you plant you foot and it kinda poodles away like something slower. The power loss is throughout the rev change. I have been told transmission filters can affect the power, but this suddenly? The shift feels normal to me. If I drop it to 1st or 2nd it seems to operate in the right gear, but no quicker.

 

[Mike97gt]

Thanks to those who have been able to offer me advice.



It started happening after the mechanic changed the cooling manifold (I still don't know the name of this part). He told me the plugs were badly worn and the car was misfiring - the car had much slower acceleration when I took it back. I checked the plugs, and he was right about them being useless. Changing them appears to have stopped the car from misfiring, but has not returned power. I am wondering whether the leak on the manifold has caused some problems... the water sprayed over the first two plugs on the passenger side, could it be that it is still in there causing one of the new plugs to fail? Maybe I should re-change those two plugs, but how can I ensure that the sockets are clean (is compressed air enough)? I'll stick with the Champions for now so they match, unless someone tells me that they are a problem.

There is no shuddering, you plant you foot and it kinda poodles away like something slower. The power loss is throughout the rev change. I have been told transmission filters can affect the power, but this suddenly? The shift feels normal to me. If I drop it to 1st or 2nd it seems to operate in the right gear, but no quicker.

do you know what a misfiring engine feels like? if you don't it will buck and shudder goign uphills and such.

first thing pull all the plug wires out and look into the plug holes. is there water or coolant or anything other than a plug in there? if they are dry then reinstall the wires.. next follow all the vacum lines and make sure they are plugged in..

this is a come back.. you need too bring it back too who ever did the work.

 

[Mike97gt]

I am wondering whether the mechanic has made a mistake piecing everything back together after replacing the coolant manifold

ok so i am assuming this work was done too fix a coolant leak? intake manifold cross over cracked?

ok one other thing you can look at. remove the intake tube going into the throttle body from the air box.. then have a friend hold the gas too the floor with the engine off and see if the throttle blade is opening all the way.

i how bad was it oveheated.. you telling me it is a lot slower now but it don't misfire.. then there is a good chance engine damage occured if this car overheated. i would get a compression check done. in fact bring it too a ford dealer and ask for a relitive compression check too be done with the wds.

 

[Col]

ok so i am assuming this work was done too fix a coolant leak? intake manifold cross over cracked?

Maybe that's the part - was originally plastic, but after a succession of failures ford now reinforce the part with metal. It sits above the enigne, and cost a reasonable sum of money to replace (600+ Canadian). The mechanic checked the plugs and said he blew some water out of the front two passenger side wells. When I replaced the set, those two came out with water on them. I could not see any water or damage on the replacement plugs upon inspection this morning.

ok one other thing you can look at. remove the intake tube going into the throttle body from the air box.. then have a friend hold the gas too the floor with the engine off and see if the throttle blade is opening all the way.

how bad was it oveheated.. you telling me it is a lot slower now but it don't misfire.. then there is a good chance engine damage occured if this car overheated. i would get a compression check done. in fact bring it too a ford dealer and ask for a relitive compression check too be done with the wds.

The accelerator opens the throttle blade fully. I could be misreading the signs of a misfire, but it doesn't shudder. The first I knew of the water leak was when the warning light came on. The temp guage was in the normal operating zone at that time, and I never allowed the water to drop low enough for the engine to overheat.

Worse case scenario is that I have to pay Ford to inspect the car, but as I said originally - right now is not a good time to be ploughing money into it. I am hoping I can find a solution before that. I have a feeling that you think the plugs may still be a problem, and I am wondering whether I should replace them again. Unless the mechanic has damaged or forgtotten something else, maybe that's the logical solution? Is there any way to check the leads?

 

[Mike97gt]

Maybe that's the part - was originally plastic, but after a succession of failures ford now reinforce the part with metal. It sits above the enigne, and cost a reasonable sum of money to replace (600+ Canadian). The mechanic checked the plugs and said he blew some water out of the front two passenger side wells. When I replaced the set, those two came out with water on them. I could not see any water or damage on the replacement plugs upon inspection this morning.


The accelerator opens the throttle blade fully. I could be misreading the signs of a misfire, but it doesn't shudder. The first I knew of the water leak was when the warning light came on. The temp guage was in the normal operating zone at that time, and I never allowed the water to drop low enough for the engine to overheat.

Worse case scenario is that I have to pay Ford to inspect the car, but as I said originally - right now is not a good time to be ploughing money into it. I am hoping I can find a solution before that. I have a feeling that you think the plugs may still be a problem, and I am wondering whether I should replace them again. Unless the mechanic has damaged or forgtotten something else, maybe that's the logical solution? Is there any way to check the leads?

i would bring the car back too him and tell him whats going on. i bet there is water in the plug wells

 

[98GTBlk]

too much oil? sounds stupid but i had a friend over fill his and his was running like crap.

 

[Col]

Thanks for you replies Mike, they are very helpful. I don't know if I can hold the mechanic responsible, as the plug wells were not a part of his job (to the best of my knowledge). He's not very forward thinking, the kind of guy who would strip a part to find a problem then put it back together again before asking if you wanted it fixed (had he suggested that this was the problem, I might have suspected that he was looking for more work).

Is there any way I can check this for myself or clean the water out? At least if I can certify that this is the problem, I can go back and ask him to clean it up. Presuming no damage has occured that is.

Not too much oil...

 

[d98gt]

Did he torque the intake manifold down or just tighten until "tight"?

I replaced my upper intake manifold, and I changed my plugs/wires at the same time. When was the last time you changed the wires?

 

[Col]

Did he torque the intake manifold down or just tighten until "tight"?
I replaced my upper intake manifold, and I changed my plugs/wires at the same time. When was the last time you changed the wires?

I have no idea whether he torqued the intake manifold down or not - what is the correct way, and how would the wrong way affect the car? There is every possibility that he has made a mistake without realising it.

I have only had the car a short time and haven't changed the leads yet. They worked fine before the manifold was replaced, and I don't have the money at the moment to start replacing random parts without a reason. Water in the plug well sounds possible because before the plug was removed for inspection, it would have been keeping the water out. When the mechanic checked to see if there had been any damage to the plugs, he could have let the water in. If I have to change the leads I will, but is there any way to check them first or obvious signs to look for?

 

[Mike97gt]

Thanks for you replies Mike, they are very helpful. I don't know if I can hold the mechanic responsible, as the plug wells were not a part of his job (to the best of my knowledge). He's not very forward thinking, the kind of guy who would strip a part to find a problem then put it back together again before asking if you wanted it fixed (had he suggested that this was the problem, I might have suspected that he was looking for more work).

Is there any way I can check this for myself or clean the water out? At least if I can certify that this is the problem, I can go back and ask him to clean it up. Presuming no damage has occured that is.

Not too much oil...

yes you can pull the plug wires out of the holes. and look into them and see if the plugs are wet. this is part of the intake job. when you remove the mainfold water gets into the plug holes.

lets eliminate this first then go from there.

 

[Col]

Cheers for all your help!

Sorry to have left this, but for a while the car became my least important issue. Since then my mechanically minded father visited me from the UK and without driving the car told me to upgrade to a better quality plug. I put in some Champion double platinum plugs after reading that they match the OE plugs, and this solved the problem.

So despite the various catalogues suggesting that standard plugs are compatible with the car, my lesson is not to go down the cheap non-performance route!

Thanks for all your suggestions and ideas.

 

[ponysarepretty]

I have an auto

I drove a manaul for the first time today... Different, i'll give you taht

 

[GDawg]

The thing about a manual vs an auto is that we (with manuals) can rev high before we dump the clutch. Our cars suck with the lower end torque. As far as plugs go, stay with copper tops instead of platinum unless you are just looking for a long lasting plug. I prefer NGK Iridiums. Also, check your wires, change out your PCV if you haven't lately. Maybe flush the engine with Seafoam. Gears will help. Other than that, be happy and don't worry. '98s are NOT the fastest car around. But a Mustang is a Mustang...