jerking at low RPMS...

[Blandnuts]

Don't go and buy new parts, find the problem first.

1. Clean the IAB or IAC (the valve everyone is talking about). Take it off the car and spray carb cleaner or something similar into it. Just make sure the plunger can move freely without sticking.


2. TPS- Check this with the key on engine off. Get a volt meter and plug into the black and the green or orange (can't remember off the top of my head so do a search). Anyways, you'll know when you're on the right wire... The voltage should be within .9 to .99 volts. If it's not then you'll have to loosen the two screws on top and adjust it to the proper range.

3. I'd also check for vacuum leaks.


Might want to go ahead and do a tune up since it seems like the car needs it. Good luck.



Fred

 

[88_GT_5_oh]

Don't go and buy new parts, find the problem first.

1. Clean the IAB or IAC (the valve everyone is talking about). Take it off the car and spray carb cleaner or something similar into it. Just make sure the plunger can move freely without sticking.


2. TPS- Check this with the key on engine off. Get a volt meter and plug into the black and the green or orange (can't remember off the top of my head so do a search). Anyways, you'll know when you're on the right wire... The voltage should be within .9 to .99 volts. If it's not then you'll have to loosen the two screws on top and adjust it to the proper range.

3. I'd also check for vacuum leaks.


Might want to go ahead and do a tune up since it seems like the car needs it. Good luck.



Fred

green wire on the TPS to the red wire on the voltmeter, and the black wire on the volt meter to ground.

.98 seems to work good for me

 

[genericstang]

ok, i will try those things probably weds(my next day off)

also i went out again tonight for like a small drive(about 10miles total) and when i stopped and got out, there was light smoke coming from what seemed to be the cats. which kinda confused me. also smoke was coming up from the firewall area. didnt see anything burning or whatever. i drove around some more and it stopped? weird.

ive already did the spark plugs, wires, cap and rotor, and air filter.

 

[88_GT_5_oh]

something might have fell on an exhaust part when you were working... 9 times outta 10 i spill oil on my headers when i put oil in, i have a shakey hand i guess.... it smokes pretty good

 

[genericstang]

ok, i changed the air filter and put in a new PCV valve. the problem still occurs.

-idle still flucuates between 500-1K
-jerks in gears 1-4 around 2K RPM when decellerating(not on the throttle)

i dont know if its vacuum leaks, but ill check and see when i go back outside.

also, while checking the TPS, i just adjust it until its right, or would i need to just replace it completely?

lastly, if those things dont work, ill replace the idle air control valve.

any other suggestions before i take it to a shop?

 

[genericstang]

EDIT// found a vacuum leak on a hose that is connected on the firewall. im looking through my haynes manual right now, but am having trouble finding what tube it is etc etc. can anyone help me out here on what tube it is, how long, width, etc. as always, thanks for your continued help!

View attachment 514345

 

[Blandnuts]

also, while checking the TPS, i just adjust it until its right, or would i need to just replace it completely?

lastly, if those things dont work, ill replace the idle air control valve.

any other suggestions before i take it to a shop?

Do a complete tune up. Wires, plugs, cap, rotor and fuel filter.


TPS- Just check it before you loosen the two screws. If it's not within specs, loosen the screws and try to get the proper volts. If you can't get it, you might have to take it off the car and widen the holes, but be careful you don't take too much off.


Clean the valve before you buy a new one. They are prone for getting dirty....




Fred

 

[Blandnuts]

Your best bet is to follow the tube and match it up with a new one. I'd also check the other lines for future problems and fix them all at once. Good luck




Fred

 

[genericstang]

ive already done tune up stuff within the past 3 months.

New Plugs
New Wires
New Cap and Rotor
Oil Changed
New Air Filter (finally put in today)
New PCV (just did today)

ill do the fuel filter next. probably sometime next week perhaps.

right now im heading back to the store to get some hoses to replace the one with a leak. hopefully this will fix the problems, if not, then ill try the TPS.

THANKS!!

 

[jbj454]

Looks like your pointing at the main vaccuum line that runs to the upper intake. I think its a 3/8", no longer than 10-12". Cut extra length to be for certain and trim any extra. My buddies car was doing the same thing with the idle, and he changed his o2 sensors and that fixed the problem. Hope this helps.

 

[genericstang]

Looks like your pointing at the main vaccuum line that runs to the upper intake. I think its a 3/8", no longer than 10-12". Cut extra length to be for certain and trim any extra. My buddies car was doing the same thing with the idle, and he changed his o2 sensors and that fixed the problem. Hope this helps.

i didnt feel like finding the other end of the hose so...i just cut it wear the leak was(since the hose was in pretty good condition) and put a connect there. and then cut a piece of new hose and connected it from the other end of the connector to the module. runs like "new" again.

ill probably still change the fuel filter next week.

THANKS!! everyone for your help on getting another 5.0 brother out of mud.

 

[Blandnuts]

I suggest replacing the line when you get a chance. I know I hate doing things twice.


Fred

 

[mrswivlepants]

Did you pull the codes yet? Don't start buying stuff from suggestions from these internet mechanics. Although these are all educated guesses, they haven't looked at your car. I had the same problem and pulled the codes. Got both codes for my O2 sensors. As soon as I replaced them it was like driving a new car. BUT, don't buy O2 sensors. Pull the friggin codes.

 

[50gt1988]

Did you pull the codes yet? Don't start buying stuff from suggestions from these internet mechanics. Although these are all educated guesses, they haven't looked at your car. I had the same problem and pulled the codes. Got both codes for my O2 sensors. As soon as I replaced them it was like driving a new car. BUT, don't buy O2 sensors. Pull the friggin codes.

First lets not start throwing around the term "internet mechanics." I can't speak for anyone else but personally I don't give advice unless I've fixed a similiar problem.
And by the way that hose that you repaired connects to a main vaccum port underneath the upper intake, its used on the Speed Density system to measure Manifold Air Pressure (MAP), very important!

 

[Blandnuts]

Did you pull the codes yet? Don't start buying stuff from suggestions from these internet mechanics. Although these are all educated guesses, they haven't looked at your car. I had the same problem and pulled the codes. Got both codes for my O2 sensors. As soon as I replaced them it was like driving a new car. BUT, don't buy O2 sensors. Pull the friggin codes.

Internet mechanics.... Do I win something?



Edit: Did you have a check engine light on when the O2 sensors went bad?

 

[90mustangGT]

Genericstang I live/work in your area.... Why don't you just PM me or Email me when you have issues. Then we will post the cause/fix of your problem later. I figure you don't want to bother me but it's no bother. If you really love your car then I don't mind helping out.

 

[genericstang]

Genericstang I live/work in your area.... Why don't you just PM me or Email me when you have issues. Then we will post the cause/fix of your problem later. I figure you don't want to bother me but it's no bother. If you really love your car then I don't mind helping out.

you disappeared from here awhile back and i didnt know what happend. lol. anyways, im going to PM you because i have some questions about parts etc. thanks again.

(internet mechanics are my HEROS )

 

[mrswivlepants]

First lets not start throwing around the term "internet mechanics." I can't speak for anyone else but personally I don't give advice unless I've fixed a similiar problem.

Don't get your internet panties in an internet bunch about this. I reinforced the best advice I've seen in this thread as of yet, given first by 89lxsport50. I gave you all Kudos when I said educated guesses. If he hasn't pulled the codes, all you're doing is encouraging people to go out and throw money right down the crapper until they stumble upon the solution.

Edit: Did you have a check engine light on when the O2 sensors went bad?

Oddly enough, I had never seen a check engine light on but I ran the codes anyway. The strange part was that I got a check engine a few weeks after replacing the O2's....turns out my egr was flaking around the same time and that tripped the light. I thought the damned check engine light was a myth when my car started running like crap.