No power, missing

[PontiacL32]

This morning I go start my car to let it warm up before I leave, I noticed it took it a second or two longer to start (usually starts before you let go of the key) and it kinda had alittle rough idle. I thought maybe it's just because it's cold. I go back outside to leave and it was idling good, so I jump in an as soon as I turn out of my driveway I start to go up a moderate hill and it can barley go and was running kinda rough. So I put it neutral and turn it off and restart it, after that the problem was gone and ran good all the way to work.

I have new factory replacement plugs, new maf, new boost bypass solenoid, and new o2 sensors front and rear with 2000 miles on them.

Any ideas what this could be? Some kinda sensor?

Thanks

[Slick2500]

Oh i just now noticed you have no cat.

[PontiacL32]

Would not having a cat cause this problem? From reading around I thought as long as I keep my rear o2 sensor I'd be okay with no cat.

Also there's no check engine light, but I'll stop and have it checked on the way home.

[PontiacL32]

It was running real good tonight so i did a WOT run, and it threw a code finally. the code was PO420 i believe, bank 1 catalyst below efficiency. Im guessing this code is because i dont have a cat and is nothing to worry about, or is it a problem?

thanks

[Fivefingerdeathpunch]

01+ cars have a cat diag in the PCM, once it figures out you don't have a cat, say good bye to good fuel economy.


As for your first issue, its hard too say. Cleaned the throttle body recently?

[PontiacL32]

Thanks for the reply. I've been thinking about putting the cat back on, but I'm not to worried about it unless its causing the problem I'm having.
Yes i cleaned it about 2000 miles ago when i changed my llim gaskets, i also cleaned egr at the same time. Would the problem be a sensor since i can turn it off and start it back up and it be like new?

[Cordellio06]

I've had a similar issue on 2 gp's ive owned, one 04 gt, and an 06 gt S/C...clicking/pinging noise when going up hills, and very choppy boost levels at random times...?

[PontiacL32]

Well the problem has come back, I put a new maf on and it fixed it for about two weeks with only one hiccup. I noticed when I drove it saterday that it was having a rough idle, and I knew the problem was coming back. This morning it was idling fine then under light acceleration it was missing, so I shut it off and restarted it and the missing seemed to be better but still there and it wouldn't shift till 2500rpm when it would usually shift at 1900rpm. So I restated it again, and that fixed it for the drive. I'm sure it will be back when I leave work.

Any ideas? I'll get the codes read after work.