Car running poorly; need advice *have codes*

[StangJonGT]

Ok, so I got a great deal on a 1995 GT, knowing it had some tune-up issues to attend to. When I bought it, the check engine light was on, it had no power, it pinged at anything above 1/8th throttle--it was a mess. It was owned by neglectful females it's entire life and hadn't had a tune up since 60K (it has 127K on it now). So, I did plugs, wires, cap, rotor, fuel filter and pulled codes. I ended up buying 2 new O2 sensors because it pulled codes for those. So now, the engine light is off, the car doesn't ping, but nothing happens at WOT. It drives great at part throttle, but literally (and I've owned a couple SN95s) nothing happens at full throttle. So, here are the rest of the codes:

122--TPS below min voltage
124--TPS voltage above normal
112--IAT sensor circuit below minimum voltage

Here's my dilemma. Apparently you can adjust the TPS on the Fox bodies by adjusting some screws on the device. I have read that ours is not adjustable, due to the computers setting the device at startup. So, is there any common fix to this problem or should I just buy a new TPS? Also, is the IAT in need of replacing? Is there a way to clean these parts and see if they work better, or are they basically just failed devices in need of replacing? Thank you for any help--


Jon

 

[HISSIN50]

I would probe The TPS wires and confirm that they are alright (Getting 5 volts reference, clean ground, and a signal return that is linear and at just under 1 volt with the throttle closed).

Both fox and SN TPS's should zero out upon throttle closing. But guys adjust the TPSs on both cars. If yours reads funky, you can adjust it.

GOod luck.

 

[StangJonGT]

Do I adjust it the same way as the fox cars? Would it be with those two screws on the side of the unit?

 

[urban96]

youll probably have to take a drill and bore out the holes that those screws go threw to give you some adjustment

 

[StangJonGT]

Bump for more answers.

 

[mo_dingo]

don't waste your time adjusting the TPS. The computer baselines the closed throttle voltage at each startup and calculates throttle position off of that.

You need to disconnect the ground, depress the brake pedal for a few seconds, then reconnect and take it for a 10mile drive. If the CEL comes back, then re-read the codes and let us know what they are.

Have you cleaned your MAF/IAT sensors and checked the ECT sensor. If not, that is the #1 priority, because they are probably nasty and not reading right, causing your WOT problems.
Scott

 

[HISSIN50]

Before adjusting, I would test the TPS to see what is going on with it.
While Scott is right, some folks have cleared up issues by dialing in the TPS. Fox TPS's zero out too, but everyone adjusts those (idle surge was not built into the programming, we hope).

Good luck.