A new issue has popped up on my car. The other day i went to walmart about a 5 mile trip from my house, started the car up at my house and let it idle for about 1 to 2 minutes, car idle just fine, cruised over to wally world and everything was fine. I was in walmart maybe 15 minutes and came back out and started the car and the idle seemed a littel rough. You could feel more vibration than normal. Thought nothing of it so i tap'd the throttle and the rpms went up to 1500 and dropped normaly but the car sounded like it skipped a beat when it got down to idle rpm about 900. Then the idle got real rough. RPM's stayed 900 but the vac went up to 10hg and was bouncing all around 14hg to 8hg all around and the car sounded like it was camming like an old muscle car. (Also the lights were dimming when it got down to 8hg. It only stayed down at 8hg for a few seconds then came back up and would go right back down, the whole time the lights would flicker) So i checked a few things. My Turbo Time said Volt. was 13.8 the whole time never moved and rpm stayed steady until i hit the gas. Tried to get the car to hold 2000rpm but as soon as i got it to 2000rpm the rpms wouldnt stay steady for nothing would bounce about 400-500rpm but never over 2000. So i shut the car off and it shut down hard.(Lots of vibration) got out of the car and it smelled like rich gas from the exhaust. So i popped the hood and checked things out and everything is tight. So i started the car back up and it started fine.

Things ive changed:
Spark Plugs : NGK 4306 gap 40
Went back to stock ign from msd
change plug wires

The car still does this even after ive changed these. Its not a common thing but happens like once a month or so. Mainly when its really cold out like 40 or below. Im wondering if it could be a tps sensor or map sensor. maybe an o2 or something just dont know. The only thing is this issue started about a month after i installed my turbo time, checked the grounds and they seem fine. Another issue that maybe related to this too is when im driving say 40mph in 4 or so the car will cruise fine and then all of sudden seem like i took my foot off the gas (sudden loss of power) kinda like a miss. If i press on the gas the car will studder bad. So i can just put it in N and roll a few 100 yards and then everything will be fine for a few miles then it will start doing it again. This also happens in all gears not just one. but if i mash the gas while it does it the car takes off with out a hitch. but can come back down to a cruise and it will start to studder and crap. Its just really irritating. Any suggestions?

 

perhaps, as you suggested, a bad sensor. sounds like your car is just 'confused' and the smell of gas in the exhaust having not been burnt seems to suggest your car is putting way too much fuel in, which would cause your car to run like ****.

and yes, the TPS is a known issue in these beasts. that will cause your RPMs to jump all over the place at idle.