The symptoms..car is starting to idle like it has a huge cam in there but have a stock cam. Sometimes it idles ok and sometimes it gets so surgy it sounds like it will stall right out but so far it hasn't. It starts up quick not a problem with that. I don't feel like its got a miss but it was way way slower than normal on my tazzo today which is like a gtech . I was consistently slower in mph with identical 60fts. Usually I get around 100 to 101mph on the tazzo and today was like 95 with even one 92 : Zero wheelspin dead hook on my nittos.

I have changed some stuff in the car..seemd had this surgy idle and occasional poor mph /slow problem for a year or two but it seems like its getting worse now. I have new gm fuel filter,put in nearly new svo 30s tuned with my maft. I have run redline injector cleaner thru car and have checked fuel pressure at idle and wot. I had zero knock on my scanmaster today.Running premium 91.

I have stock spark plugs.66,000mph on car,stock o2s, stock plug wires and think first opti. I did lose a water pump forget if it was this spring or last.
Car pulls to redline but does seem to be pulling slower up top.
I also cleaned my air filter and recharged it not very long ago and maybe my maf is dirty will check it. I had egr disconnected but connected it again.
I still have cats on the car .
I don't see any check engine light on.
So what do you guys figure..

 

All I could suggest is that a good tune up might help ya.

 

Toss the MAFT and get a real tune.

 

My car had the same symptoms, and unfortunately it was the opti. So it was changed, and the car ran fine for about 8 months. I ran through a couple of puddles and now the same thing. It's time to get a delteq or a LTCC or something.

I'd suggest checking your plugs and wires, including your coil wire, and make sure your MAF sensor is clean, and your TPS is functioning properly. Failing all that, there's one likely suspect.

I'll be tearing my opti apart this weekend or next, let's see what it's made of.

 

start with the basics. plugs and wires. if theyre stock, it might be time for a tune up anyways. also, checkout a scanning software so you can monitor your engine. ive found this makes a world of difference trying to diagnose your engine problems. youll also be able to see how your o2's are responding.

 

I have a scanmaster lt1,have hpp with old scan chip and autotap. I have scanners..
Today I cleaned my maf and changed out my tb for a used BBK 52. See how that goes. Idle seemed better but didn't drive the car long enough to see if it
is running better. I realize a dirty maf can slow a car down and a dirty iac can maybe screw up idle. See how it goes maybe tommorrow. Too wet to try car out tonite.
I think will put the autotap on the car that has got most detail and check misfires and stuff when the idle goes to heck if it still does. I woud have though bad misfire would set the check engine light though. No lights at all.
I even took off my air pump crap .