This started last night and rapidly grew worse. I was drivin a few times in the pouring rain and at one point the idle dropped to around 500rpms and the car shook pretty nicely. Then later on in the night it was doing it again and the car would burst back to life again at random. This morning i had to drive my mom to get her car and the car started out fine (maybe an open loop-closed loop problem) and then all of a sudden the rpms started droppin low again. Then the car felt like it was dragging a huge weight behind it. I am way low on power and it seems to drag at least first gear out til almost 3000rpms. And every now and then there is a sudden burst of power back. Sometimes this occurs right after shifts sometimes midway through the power band. Its really strange and difficulty to drive, any ideas?

 

My 97 Z has a miss due to a bad plug wire and I'm stuck in a fixed loop mode due to a bad Crank Pos Sensor, and my car feels the same way at times. Run a OBD2 scan tool on it while you drive and see what it logs. Reset the codes and drive a fixed set of miles (Say 40) and then check the codes and when exactly they failed. Note if that was when it ran rough and it should help you to find exactly whats causing it. According to OBD2, my Crank Pos Sensor died 292 miles ago.

 

I dont have anyway to scan it so im stuck troubleshooting. Its definately a closed loop sensor issue it feels like. The second the car goes into closed loop the rpms drop to 500 and the car starts running really crappy and sluggish with a few bursts of life here or there. The fact that it drags first gear out to like 3000rpms (very slowly of course) i think is because im giving it so much throttle just to get it moving. So i assume that means the tps is working (which isnt that supposed to be on in closed and open loop anyways) so Im thinking maybe the Maf? what other sensors can create this kind of symptoms?

 

so i had my buddy come over and we switched MAFs. I drove the car around and it ran fine, i made sure to get into closed loop and everything and it still ran fine so i figured i guess it was the MAF. Then i put mine back in to have a control in the experiment and once the car got up the street it started acting pretty crappy again, all the same symptoms. But it only lasted for a short bit and then the car ran normal and continued to run normal as i did laps around the neighborhood and back to my house.

So on one hand im thinking definately the MAF, but on the other im thinking.. the car is fine again?

once again stumped

 

Maybe the time it took you switch MAF's was long enough for the PCM to reset itself? Just throwing out ideas...

 

beats me.. but i drove again today and the car started acting ****ty again so i stopped it where it was and unplugged the maf and it ran fine for the remainder of the time i was driving so im thinking a definate yes for the maf?

 

He can't scan his 95 with an OBD-II code scanner.... its OBD-I. And it doesn't have a CKP sensor.

What is "fixed loop mode"? I've heard of open loop and closed loop, but not "fixed loop".