When my 5.0 (88 EFI) is cold I seem to have a dead spot in the throttle response. It runs and idles great. It's just that when I barely give it gas in this "cold" stage it hesitates as if I'm cutting the gas. I can press the pedal a little harder and it runs as it should. Once it warms up this problem goes away. I'm new to the EFI 5.0 and wanted to know if this was normal.
I'll note here that I have checked the TPS voltage and it was 1.06 - I have moved it to .996 and it has made no difference in the cold throttle response. Also, the throttle cable is tight and with no play.
Have you run codes? Might have a sensor out of whack.
Haven't run codes. Thought I would check here first for tips or ideas. I had considered disconnecting the battery and letting everything reset itself since the TPS move and the new dual exhaust and see if the occurance shows back up.
I have fixed that problem several times with....
You guessed it: a new TPS. However, in each case the computer did throw a code for 'TPS voltage out of range'. Assuming the EGR isn't clogged enough to affect driveability (and not throwing a code--a miracle on a 1980's Ford), the TPS is the logical place to look for this kind of problem.
I had a '87 Stang with the 2.3 that drove me nuts with that problem and it had no codes... Problem was the TPS... Finally found by using a buttstuffoge meter, it had a slight dip in the voltage on acceleraton. Wasn't enough to throw a code, just made the EEC think you had let up a little on the throttle...
Could the TPS correct itself when the motor warms up? The dead spot is very subtle and goes away after the motor warms up. It may be buttstuff but this Cougar is new to me and I'm trying to work out all of the bugs - no matter how small they are.
It could also be a borderline bad O2 sensor, which may or may not throw a code. That would explain the temperature related issue.
Again, it's all guesswork without the computer's codes being scanned.
Scanning when I get home this evening. I'm curious fi what I'll find. All of the "problems" that I am having with the car are very subtle. Get something new and you notice everything!
I ran the codes and it threw a #34 - PFE or EVP circuit above the closed limit of .67 volts.
So what's my next move, replace the EVP sensor? Should I disconnect the battery and reset everything afterwards?