Thread: Various Issues with the 00 GP, might have finally figured it out?!

I have made a few threads months back about my car and the odd things it did. A recap, unsteady idle, hesitation on pullout but only occasionally, hard shifts under moderate throttle 3-4.5k rpm, Hard/long starting. Anyway, I had mentioned that i found UIM bolt sitting on the intake, not threaded in at all. I tightened it down and also torqued the others (that i could manage to get to) to spec, and none were to spec, so idk whats is with that. Anyway, the issue's still persist, but now 3k rpm's plus i have a turbo like whistle noise that gets louder the higher i rev it. Car only has 48k on it, but it's sounding more and more like a UIM gasket to me. Anyone's opinion is greatly appreciated!
Also, should mention I used a smoke machine (all be it a homemade one, that runs on mineral oil) to check for vacuum leaks, but didn't see any. Also looked for any lose or off hoses, didn't see any.

I would say give cleaning your MAF sensor a shot. As for the whistle noise that may be something else.

Oh forgot to mention, that is something i tried

I wouldn't think the dreaded leaking intake manifold yet at your low miles, but obviously the car has been sitting for considerable time. I am a little suspicious of why the one bolt was not threaded in & the rest not to spec. Somebody must have touched it at some point. Telltale sign of a UIM leak is coolant pooling in the valley between the manifold & heads. Also if you spray brake cleaner around the manifold it will make the engine rev up by itself.

Usually a whistling noise indicates some kind of vacuum leak. If the pcv valve was replaced with an aftermarket (non-acdelco) the whistling could be coming from that or if one of the two O-rings is missing in there or the map sensor hold down could have a broken tab. There was a design update which GM sold when you ordered a new pcv valve with a stronger hold down. Could also be one of the accessories running off your drive belt on its way out.

Couple other things to try is cleaning the idle control valve, check the vacuum hose of the fuel pressure regulator (pull it off, no fuel should be dripping out) and as mentioned above clean the MAF sensor and check the wiring going to it

If you have access, watch fuel trims. Lean would indicate a vacuum leak as well.


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Took the oil cap off today after i got home today. Now that i think of it do notice a faint whistle at idle now that i think of it, but when driving only becomes very apparent after 3k rpm's. Took the oil cap off and seemed to have a zero effect on idle speed or sound. Inlet tube looks fine.

New development today, engine light code P0102 Mass or Volume air flow A circuit low. Finally set a code, was worse then usual today when I would switch directions and be turning the wheel at the same time, the rpm would dip bad and power steering would weaken briefly and the car would make a weird noise. Idle was unsteady, even had a few weird shifts where it shifted at weird times I cleaned my MAF before, so I'm guessing that the I'm gonna need a MAF and hope that fixes all the weird problems I've been having.