A friend of mine has a 91 Firebird with the 3.1. He says that it runs rough and struggles a little when it's first started up after sitting for a while. Once it's warm it seems to run fine.

He just got the car this ummer. We changed the plugs, wires, air filter and oil a couple of momnths ago. I'm thinking it might be a sensor. Any thoughts?

 

i've got a similar problem, start with the egr valve and work your way around


i'm gonna try and do the iac next

 

I had the same problem man. Was the digital EGR (exhaust gas recirculation) valve. Dont try and buy on from GM or any parts store though, cost ya like $350 or more. Found one for $45.00 on ebay though . I think all the ones on 3.1, 3.4, and 3.8 from 1990 to 1994 or somthing will work. Dunno for sure though.

Good Luck!


~Max

 

3.1 and 3.4 might both work, not the 3.8 though

 

You are suggesting replacing the oxygen sensor to send better "cold operation signal" to ECM for open loop cycle? (when engine is cold)
I've had this problem on my 1985 for awhile.
Happens when cold, yep. Changes to perfect when warm.
I get great "have to floor it" operation, while engine is cold, tho.
Haven't changed oxy sensor in a bit. Engine has run very well for many miles.
Thanks for the clue.