thank you for all your responses...just wanted to give u guys an update with wats going on with my monte....took it to the dealership for the 2nd time today...the mechanic said he finally thinks he figured it out...he said i need a coolant temperature sensor...he said its out of range...so he ordered the part but it wont be in till monday...so i gotta bring it back on monday and hopefully this will fix the problem and then we can go from there and i can finally get the car inspected

 

btw...chibi what kind of grille is that on ur monte? that would look sexy on mine haha

 

Step #1, find a new mechanic. The only way the coolant sensor plays into this is if your car was over heating. To my knowledge the coolant sensor does the following:
- Feeds the PCM and gauge in you instrument panel what temp the car is.
- Based on the temp sensor, the computer knows when to turn on the fans.

If you wish to still go to this mechanic, I'd ask him that he refund the cost of labor if this does NOT fix your problem.

BTW - Do you happen to have the codes off hand that it threw?

It also sounds a little shady that the dealership claimed to have "fixed" an O2 problem and you said within about 30 miles you get a code referencing the O2 (I wonder if they just cleared the code). Which O2 was changed (upstream or downstream). Downstream is the one after the cat. If you are throwing a code for the downstream one, it could be the O2, but if that O2 was changed, you are more then likely looking at a cat failing (the downstream O2 on these cars does not affect performance, they simply monitor the cat).

I'd still dive into cleaning the MAF and IAC (fairly easy, when cleaning the MAF you just need a can of MAF cleaner from the parts store and follow the directions, piece of cake). I would also inspect for vacuum leaks (those may relate to evap codes).

Again, unless your car is overheating, a temp sensor will have no bearing on these issues. A good indicator if the temp sensor is working, watch the gauge from a cold start, it will rise and eventually then the T-stat opens it will then drop a little and then it may go up a little down a little (depending on outside temp and how your driving is). But if goes up and then takes that drop, your one and only temp sensor is working just fine. But, if you have good heat out of the vents, the gauge never moved, then you might have a bad temp sensor (or a dash problem). If the gauge goes up and continues to climb and never comes down, you need someone with a car scanner to read the computer and see what temp the computer has (if the computer reads what should be normal temp, but the dash is pegging high, again, not a temp sensor). But if the computer reading matches a high dash reading, you either have a bad temp sensor OR the car really is over heating.

Sorry for the mile long message, but I really think if the mechanic claims it's the temp sensor for all those issues, he's ripping you off (or does not know what in the world he's talking about).

 

I agree, the coolant sensor failing would make the temp gauge fail. When that happens, the fans turn on and stay on for 2 minutes after you shut off the car.

My grille is an slp grille, find it on ebay, put it on with double-sided tape

Feel free to pm me if you wanna talk about my ride

 

well i havent been paying for anything because i keep bringing it back to the dealership...if the issue isnt fixed after monday then im going to my own mechanic and have him look at it because i can't keep going through that everytime i get gas...and i did buy a new gas cap just incase...this is really getting ridiculous...and the temp gauge does move around alot...the other day it went kind of close to the red as i was parking but it hasnt done it since. but its deff not overheating

 

If you have gauges going erratic and you KNOW the car is working properly there is something called a "Stepper Motor" that is probably going bad.

 

just wanted to give u guys an update...the dealer replaced the coolant temp sensor, mass air flow sensor, and the vent purge valve and the car is fine now...i got gas right after i left the dealer and it started right up with no problem. check engine light came back on again so im gonna get the codes pulled again and just go to my mechanic...but its running 100 times better now

 

Ouch... having a shop do the MAF sensor was probably like $400

 

yeah they didnt charge me anything at all...only thing i did was pay for the vent valve because they didnt think that was the main problem...but it was...it was worth the $22

 

If I paid labor to fix a problem and it's not fixed, I'd want some money back. Not to mention if they are throwing parts at it just for the sake of throwing parts at it, that would irritate me too. Did they say why they changed those parts (what pointed them to that)? Also, did you ever try the MAF Sensor cleaner??