Noob with a new(to me) Grand Prix-- Rough idle question

[awildryan]

Hi all, I recently bought a 2001 Grand Prix GT, it has high mileage(177,000) but it still runs and looks great.

Although I did have one question, the car will sometimes idle rough, and sometimes normally, also if you give it a lot of gas(with the pedal not in the tank) it sometimes will hesitate before it revs up and other times will just jump on it and go. I recently bought a new Mass air flow sensor for the car, and it helped a bit, but I was wondering if anyone had any idea of another part to replace (I was thinking throttle position sensor?).

Thanks in advance

 

[Sushamouf]

Possibly tps, could also be a map sensor. Have you tried a tune up? Plugs, wires, fuel filter.

Sent from my Droid

 

[nos4blood70]

How's your upper intake manifold? Any work ever been done there? Still got coolant in the reservoir? Mine was behaving as you described as it swallowed all it's coolant and hella tons of water because of the failed UIM.

 

[awildryan]

Oh yeah probably should have mentioned that sorry, I gave it a full tune up myself, and for the upper intake manifold it hasn't been touched as far as I know. Lastly the reservoir is full, also checked the radiator itself when I got the car, and it's got coolant in it. Thanks for the ideas guys I'll be sure to check that stuff out

 

[nos4blood70]

http://www.grandprixforums.net/97-03-na-l36-uim-failure-60667.html
Might wanna check this out.

Issue solved.
http://www.grandprixforums.net/how-mod-lim-46931.html

 

[awildryan]

Alright, that seems simple enough, thanks much

 

[Dee23]

Bill has posted some nice threads.....But if for any reason you feel that the upper/lower intake manifold gasket is to much to do at the momment, just try cleaning the entire throttle body, make sure the EGR pintle valve isnt sticking(clean EGR passages while your at it), clean IAC valve, chech IAT sensor, check/ clean MAF(Im not a big fan of cleaning MAFs but sometimes it does work), make sure air filter isnt clogged/dirty. Those are the really easy simple things to check....fuel filter is deffinately a possibility. And also, your sensors may be intermittent(voltage dropping on loads)

Again, this is easy stuff to start off with, but with 177k it may very well be the UIM/LIM gaskets but if you've been maintaining ya motor it may not be. 177k is plenty though, but just inspect all around ya plenum or s/c for signs of wear and tear and check ya oil(make sure its no other color than it should be)