88 GT feels a little sluggish.

[fost9508]

Guys,

Not sure if I will be able to get good responses to this question, but I will try anyway. I have an 88GT no MAF 5spd tranny. The car seems to run a bit on the sluggish side, and the mileage I think is a little below average, I have no basis for comparison, just my gut feeling. I have no idea where to begin looking. Here is what I have done so far.

scanned the car. The only code I can't get cleared is the EGR valve code and the air managment codes 44 and 94. I am working on getting these fixed right now. The egr code could explain the gas mileage.

Replaced plugs with Bosch platnum 4's and the wires with bosch 8.6 mill wire. Will plan on replacing the cap and rotor (any recommendations for a daily driver, I do want performance, just not racing prices ) Compression checked engine all compressions are at 185-195 psi, dry. So that is good unless the high compression is due to carbon build up....Re-adjusted TPS voltage, set to .98.

I know I have to replace the motor and tranny mounts.

Any ideas, or ways to figure out where my problems are.

Thanks

Jared

 

[5.0Droptop]

If those plugs you installed are the non gapable kind i would remove them and put a set of autolites or motorcraft plugs in it. I would set the gap at around .052-.054 bump your base timing up to 12 degrees. If you need a good SD site try the link in my sig 50tech has a lot of good info on sd. Dagger on this site is a SD guru as well.

 

[fost9508]

Thanks for the response. I do have the pre-gapped plugs. Why would it make a difference?????

Thanks,

Does anybody else have any ideas for things I should look into?

 

[HISSIN50]

Thanks for the response. I do have the pre-gapped plugs. Why would it make a difference?????

Thanks,

Does anybody else have any ideas for things I should look into?

i think what he was going for with the Autolite and Motorcraft recommendation was to run copper plugs (they also make plats).

plats cannot be re-gapped - if you do, you scrape the plat off. some EFI stangs dont like plats - idle and high RPM operation is affected. some cars dont mind them.

the FRPP wires are ~40 bucks and a nice wire from what every one says. i might try them (or some Taylors) when the time comes.

i would pursue the EGR code further. if the valve is allowing inert gasses when it should not, this will affect the SOTP feel.

good luck.

 

[vikingpower]

works good

get a MSD cap and rotor kit, its got thicker brass points than the standard ford stuff, pretty cheap from Summit. Next thing you gotta switch to mass air, the kits about 500 but its very necessary if you get addicted to more HP.

 

[vikingpower]

also

take the air silencer off, its a free 5 HP. Go to a book store and pick up "5.0 liter ford dyno tests" its a really good book they dyno all kinds of stuff.

 

[90mustangGT]

Have you checked your fuel pressure? Where is your timing set?

Get some carb cleaner (TB cleaner isn't as strong) and clean out the TB. Then with the engine at operating temprature hold the rpm at at least 2K and spray that stuff down the intake as it runs, opening the TB and shutting it and this will clean any deposits from the inner intake and the valves and intake ports, will also clean the combustion chambers. Put some fuel injector cleaner in the tank. What about the fuel filter, if it hasn't been replaced within the past 15-20K miles, put in a new one. Ditch those plugs and put in a set of autolite 25's or a standard copper plug. Gapped to .050-.055. Advance the timing to 12* for starters. How about dumping the silencer and put a K&N in there.

 

[HISSIN50]

carb cleaner can eat the teflon out of the intake. TB cleaner should not (which is likely one reason Jason has noted that it is not as strong).

 

[90mustangGT]

carb cleaner can eat the teflon out of the intake. TB cleaner should not (which is likely one reason Jason has noted that it is not as strong).

I've heard of Teflon being used in TB's to prevent sticking but a good TB won't need it. I didn't know they were using it in the whole intake? Not doubting, just never heard of that, but very easily could be true. I could see where carb cleaner could eat into sensors that are made of plastic, so maby just use TB cleaner.

Speaking of TB's, check the TPS sensor. With KOEO (key on engine off) check the sensor voltage between the red and green wire, sould be as close to .999 as possible.

 

[fost9508]

Thanks guys….lots of good information. Let me see if I can address some of the questions and comments. I have a guarantee with the bosch plugs so I guess I will send them back. TPS voltage has been set to .98 volts, best I could do. I have a K&N filter on the intake, with a MARCH ram air deal on the filter that was on the car when I bought, it grabs air from the fender well. I will try the TB cleaner next time I get a chance and the fuel injector cleaner. The fuel filter was replaced about 2 years ago and has only had about 2-3k miles added since the replacement. The mass air change out is on the list of “to do” items, but 500 is a lot of money, amy want to try and find on in the junk yard. I am not sure what the timing is set at, and I don’t have a timing light, guess I need to purchase one. I am sure I could find out how to do the fuel pressure check from my chilton’s or Haynes manual, but any tips would be appreciated. Do you recommend a fuel injector cleaner? I suppose the only way to find out if one of the cylinders isn’t working is doing a cylinder balance test, right?

Thanks again for the help.

 

[HISSIN50]

cylinder balance is good for testing injectors. one cant test each plug wire for spark, if desiring (if you have a decent miss - does not sound like it).

there is a schrader valve on the fuel rail (pass side). one can hook a FP gauge up there and get pressure.

good luck.