I have had a problem with my 2.8 surging and stalling and backfiring when cold. It would stick around for a minute or so, and then it would be OK. I fixed once during a tuneup, but I was unsure what the fix was specifically. I replaced the O2, wires, plugs, cap, rotor and cleaned the IAC.

The problem recently returned, and I replaced the things one at a time to pinpoint the problem. It was carbon buildup on the IAC. I cleaned the IAC and it's port with brake cleaner, as well as the throttle body area in general. Now it starts and runs great. I know several people like connecticutfiero were also having the same problem, and I can say with certainty that cleaning the IAC will fix the problem!

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Thanks Aus!
More info at: https://www.fiero.nl/forum/Forum1/HTML/043357.html

I wonder what is making the carbon build up returning so soon.
Don

I see that all the time at work on all different types of cars. It make a huge difference when you get all the carbon cleaned out!

Carbon build up in the T.B. area ?? Take a look at where they located the engine breather hose, the hard part that runs back to your rear vavle cover, have you ever seen what comes out of that thing when the air tube is off and the crank case is shooting off all its vented goodies --right into your T.B.