My 85 Firebird has a rough idle after the engine is warmed up. I replaced the EGR valve a few months ago and that seemed to help some. I replaced several of the rubber vaccume lines too. I have also cleaned the IAC and quite a bit of the trottle body, but the car still idles rough at stoplights after I've been driving for an hour or so. My catalytic converter looks pretty rusty. Could the problem be that my cat. is going bad? I'm thinking about just replacing the cat. with a piece of pipe. Does anyone think that would help?

 

Ever think of the O2 sensor? I had that got bad in my '88 and that's excatly what it did to it, almost had to keep the foot on the throttle a tinsy bit to keep it alive. I'd say check that AND rip that cat off...

-Ray

 

I'd say go cheap to expensive. My car had a rough idle a lil' while ago turned out to be several thigns, but we'll get into that later. First off, i'd say replace that cat w/ a piece of piping or go w/ a catco hi-flow (but piping is cheaper). Then doing that O2 sensor wouldn't be that bad of an idea also. Check for those vacuum leaks once u get under the hood and also look at ignition wires etc. When i had issues w/ mine one problem was corroded wires going from the coil to the MSD box, the splice wasn't done great, and the moisture had rusted the wires out....Also had a problem with my MAF Sensor, was broke, i had suspected that b4 and picked up a remanned one from a friend nad put it on, but the shop gave a code saying it was broke too...so they put on a new-remanned one and it works flawless (knocking on wood). Keep us posted.

 

I forgot to mention that I did put a new O2 sensor in about a month ago. The )2 sensor was a pain to change. I had to put a pipe wrench on it and use a bottle jack in between the wrench and the ground to get that thing to bust loose. I really didn't notice a difference with the new one.

I plan on swapping the cat. for a piece of pipe in a week or so when I get time. I just wanted to get a few other opinions. Thanks.