So lately my jeep is struggling with life. I have a 89 4.0L and lately sometimes when i go out and start it, it will start and rev up to a little under 1,000 rpm, then drop back down to 200 fast, and then work its way up to 750-800ish.... usually it will start and then rev up to 1800 and drop down to 1,000 and then gradually down to 800. Sometimes it will work normal... and sometimes it has issues. My jeep doesn't idle very well... at all.. its very jumpy and it misses. And its been that way for a while. My TPS is adjusted to .85ish volts. I have new injectors. I have a brand new CPS, IAC, and Knock sensor. My gas milage sucks too... My O2 sensor was replaced just before i bought it in 2009. Please help.

 

when your replaced those parts did you reset the computers adaptive memory? If not try that and the TPS should be between .60-.70 volts

 

Are you saying the difference between input and output voltage should be between. 4 and. 6? I was told its supposed to be as close to .83 as possible

 

How do you do this? I just replaced a bad CPS and still have issues maybe doing that will help

 

Yeah i have reset the computer several times, it doesn't seem to make a difference.