Hey all!

It's been a while since my last post, but I'm always on here looking for answers (stalking much?). I just cleaned the contacts on my ignition switch (last night!!) using this thread http://www.grandprixforums.net/1999-...ferrerid=15750 so my fan would blow, and replaced my radiator (cracked), and thermostat (stuck closed). All of this was done with help from awesome friends within the past couple weeks.

Anyway, as you can tell by the title, emissions are coming up and I have procrastinated--again.

Problem #1 Code P0102 MAF
Possibly the MAF, but just replaced 2 years ago (with last emission test). Fixed a vacuum leak and throttle body has been cleaned as well as the MAF with cleaner. Issues given: hesitancy with acceleration occasionally, bad gas mileage, and RPM's jumping when first starting (1000 or more per jump).

Problem #2 Code P0171
Thought I fixed this fuel trim thing-a-ma-bob with the vacuum leak repair (there might be another). My car always smells a little gasoline-y, so running rich. I really feel these two codes are intertwined.

Problem #3 Hisssssssing coming from rear of car (not leaking tires)
It is a constant hiss which sounds like it's coming from the rear tire wells. It happens in any gear and only while the engine is running. With the searches I've done on here, I don't think it's the fuel pump (no hissing when key on but not car) and the noise is constant and same pitch and intensity from both sides. This just started today after I was driving for about 15 minutes. I noticed it when I was at a stop light. Turned off my air (on all 5 speeds finally!) and rolled down my window. Stopped at a gas station with car running and it's both sides. Turned off car--no latent hissing.

If anyone has any suggestions or ideas, I would be eternally grateful. Willing to try just about anything to get these Gremlins fixed.

P.S. Stock engine down to the stereo. 99 Grand prix, naturally aspirated. If anyone is in AZ and wants to play car, let me know.

Sherry