My car will stutter/stumble in gear only, not in Nuetral or park? It also seems to have lost a little low end power. From lets say idle to 2k. Car has 57K. WIres maybe? Plugs? Is this the infamous lt1 stumble?

 

bump

 

The opti should not be giving you trouble at 57k but it has happened before.
I would do a tune up (plugs and wires) and see if that helps then go from there.

 

Sounds to me like you have the dreaded EGR problem. Try disconnecting the vac line to the EGR and plug it. Then take it for a ride. You can clean it and check the gasket for leaks. You can also push the diaphragm with your fingers and see if it feels "rough" as it moves out and back in again. Let us know what you find out.

 

Hold up- EGR was valve was replaced w/ new delco unit few thousand ago. When that went it was more of a violent chugging. This is more of a stutter, like a cylinder is just cutting out or like someone is hitting the car with a hammer.

BTW, it does it up to 1.7K rpm, but it is not always constant. It is just not that smooth. If you hold the rpms at 1.5K rpm in nuetral or park, it will have this stutter? AT idle it is occasional, sometimes bad, sometimes not.

I am gonna do a tuneup soon but my mechanic has to fix two other cars we have first

 

Hold-up maybe your IAC has some carbon build up on it. I'm confused in your first post you said "not in Nuetral or park" but in your last post you said "If you hold the rpms at 1.5K rpm in nuetral or park, it will have this stutter" Well how can we help you if you change the story.

Do the IAC and TPS while your at it.

 

Hold up again New IAC motor about 2 or 3K ago. Didnt really help anything. Sorry, forgot to mention that. TPS looks okay on scanner.

What i meant by not neutral or park is that when there is no load on the motor it is "smooth," relatively speaking. IT wont stutter in neutral or park just idleing (sp?) but if you rev it to 1.5k rpm in neutral or park it kinda stutters; it keeps the same rpm, but isnt smooth, it has miss or a minor cutting out in it. It is a very odd problem. It is more pronounced under load. Sorry, but it is the best i can do over the net.