Hello,

I literally just started having this problem 20 minutes ago. I went and picked up my mom to go to lunch with her today and afterwards when dropping her off the RPM is bouncing up and down. Normally sits about 800 idle and its jumping to about 1500 RPM, then back down.

On the way home stopping at a red light the RPM jumped again and it lurched forward, thank God no one was ahead of me. Then when starting up the RPM dropped really low, to almost stall, then jumped up above normal and allowed me to keep going. It was doing this practically all the way home.

Idling it in the driveway with the hood open I don't notice anything out of the ordinary (except the exhaust leak, I have a new exhaust from SLP to put on) but I know that shouldn't affect whats doing on with it right now. It idled fine for about 2-3 minutes, then dropped and jumped to about 1600, then idled fine again.

Anyone have ANY clue as to what could be wrong? I got gas a few days ago and am down to 3/4 tank remaining, so I don't think it'd be bad gas or I would've noticed it right away, right?

Any help will be greatly appreciated
-Dave

 

Hi Dave and welcome to the forum!!
I had that same thing happen to me on my 1999 Grand Prix I had and it turned out to be the Mass Air Flow Sensor had gone bad.
I am sure others will post with what they think is causing this also!!

 

Thanks P343, I appreciate the quick response.

I'll have to take a look at it and try to determine if its going faulty then. I am just boggled because it just started all of a sudden.

 

Mine started all of a sudden too and was intermittent and then finally went out all together.
You can always try cleaning it first to see if that helps but be very careful in doing so.

 

I had my mass air flow sensor go out and it was night and day difference. Worked fine one day and was junk the next day. You can try cleaning it with maf cleaner, if that doesn't help you can unplug the sensor and see if it runs better (this will throw a code)

 

So I got the Mass Airflow Sensor in yesterday, replaced it, and took the car out for some testing. Seems to run fine, however, when I was shutting it off and starting it off, say 6-7 times, 1 time the rpm's jumped up, 2 other times the car started, promptly stalled, but upon refire ran fine.

Could this be due to the computer needing to relearn with a new MAF Sensor or is there something else potentially wrong? I was reading that the MAP Sensor works in conjunction with the MAF, so could that have a issue as well?

On a side note once I get a nice weekend, I have new plugs and wires to put on too.

Hopefully someone can help with the new issue!

 

*Starting it up

Sorry, talking to people and trying to type don't mix I guess. I don't see a way to edit the post either, otherwise I would have just done that instead of double posting.

 

I would give it a little bit and several drives before spending the money on a MAP just to make sure the car's computer system is not trying to re-learn something.

 

Check the MAF sensor inlet screen and the port where it goes into the throttle body for blockage. Also check the throttle body screen for blockage. The throttle body may be dirty. Also check the PCV and it's port for blockage.