Help with '94 Mustang

brightwhite98GT · Jan 9, 2010

I recently got a 1994 5.0 liter. I ran the diagnostic test today and its telling me that I am running lean at full throttle but rich at idle. Its also telling me I have insufficient throttle position change during throttle response test. It says my throttle position sensor is below min. voltage, and it did not run the O2 test because my RPM's are too low. Why would I be lean at full throttle but rich at idle? Is my TPS adjustable or do I need to buy a new one? Could any other underlieing problems be because of the O2 test?

mods include EGR delete, AC/SMOG delete, shorty headers, MSD cap, MSD ignition, cold air intake, and the exhaust is temporarily dumped after the H pipe. Thanks !!

brightwhite98GT · Jan 9, 2010

okay so I was told on another forum to elongate the screws on the TPS to adjust it. I got a reading of a .91 and I was told it should be around .98-.99. I took the throttle body off so I could get to the screws to adjust it, and there is a ton of oil laying in there. Why? I know a little oil will get in there by why so much and how do I fix this?

2002BLGT · Jan 9, 2010

What MAF is on it ? you might want to replace the TPS sensor if the car is fairly stock then there is no real reason it should be out of adjustment

blkmcnasty · Jan 10, 2010

Keep an update of what you find brightwhite because i may be having the same problem as you. I always have an uncomfortable amount of oil in my throttle body and my car is running rich (or at least it smells like it). Btw i have a 95 5.0.

brightwhite98GT · Jan 10, 2010

MAF is stock. After adjusting the TPS I got it so its bouncing back between .98-.99 although I still may end up replacing it. I cleared out all the diagnostic codes, cleaned all the oil out of everything, cleaned the MAF, replaced the fuel filter, and bought a new PVC valve last night. It definitely is running alot better BUT still not what I feel it should be. I think that may be because all the oil and Im gonna need new spark plugs after I get the oil problem fixed.

blkmcnasty - I am keeping records man and I tear it apart alot so if I figure something out I'll put it up here. Im building another motor for the car (5.8) as I get money so I may just say the hell with it. For now I think Im gonna make an oil catch can so at least its not gumming up my motor. I just dont understand why the pressure is so great its blowing all that oil into the intake.

Paul · Jan 10, 2010

How did you adjust the TPS? There are metal sleeves fixing the sensor in place.

2002BLGT · Jan 10, 2010

did you check the TPS voltage with the engine running ? if not then do that and see if its over 1.0 when the engine is running

brightwhite98GT · Jan 11, 2010

Did not check the voltage while it was running. I was told to do it with the key on, engine off. I will do that though. I just took a drill and kinda make the holes bigger. It really doesnt matter if I break it if I still have to replace it. Also, I installed the new PCV valve. You guys think an oil catch container is a good idea between the intake tube and the oil fill?