Thread: Car running funny

I will try and make this as short as possible...

I have a 99 GTP. I bought the car with 60k on it. The acceleration was boggy since the day I got it. I replaced spark plugs and wires, fuel filter, cleaned the throttle body, and put multiple cans of fuel injector cleaner through the gas. The problem was made slightly better after all of this.

I read a lot of online posts saying that this is usually the MAF sensor. So I got a new one, installed it, and it actually got worse. After the new MAF was installed, when I was cruising at 1500-2000 rpms, the car would rock back and forth. I had an 03 GTP in previous years that had this problem when I bought the car, however, I do not remember how they fixed the problem. I unplugged the battery for a day and let it reset itself and the problem went away (or wasn't as noticeable).

Fast forward 3 months to the current time. I was driving home from work the other day, and the car was sputtering at a light like it was going to die. I made it home fine, and let it be for a couple days. Unplugged the battery again to let it reset and it was driving okay for about half a day then started sputtering at stops again. At the time I noticed I was getting something like 10-12mpg, as well. I then got a P0170 error code (I believe). When I looked it up online, it said to make sure Long Term Trims were between -10 and 10; they were at 15+. I swapped the o2 sensor (pre-cat) and the problem persisted. I then put the old MAF sensor in, and the LTT's are between -10 and 10 for the most part but occasionally spike above 10 to the 12 and 14 range briefly. At the current time I am only getting 16mpg on the highway!

My questions for ya'll is: Did I get a faulty MAF sensor? Should I order another MAF sensor or leave the current (original) one in? Is it normal to spike up to 12 and 14 LTT? I am pretty sure I do not have any vacuum leaks, but I am not sure what hoses are vacuums, so I checked them all and they seemed fine. On my old 03 I was getting 24-26mpg highway; any ideas why my MPG is so low? It is killing my wallet!

THANKS!!

Scottydoggs, I bought a "Standard" brand MAF. I believe the one that came with the car was the original. Should I just buy one from the dealership, rock auto, or go to a junkyard and find a car with low miles?

I do not have a vacuum leak. Any other options?