Ok, I finally got my fiero on the road this week. Drove it back and forth to work all week, but drove it for an extended period for time for the first time this evening. After about a half hour of driving it developed an exhaust leak, major loss of power and occasionally misfire under heavy throttle. I pulled over and found that 2 of the exhaust manifold bolts had walked out. My question is this. Could an exhaust leak cause a loss of power and/or a misfire? I thought these things were simple enough that the engine computer wouldn't be able to try and compensate for an exhaust leak, but maybe I'm wrong.

quote Originally posted by irish_motorhead: Ok, I finally got my fiero on the road this week. Drove it back and forth to work all week, but drove it for an extended period for time for the first time this evening. After about a half hour of driving it developed an exhaust leak, major loss of power and occasionally misfire under heavy throttle. I pulled over and found that 2 of the exhaust manifold bolts had walked out. My question is this. Could an exhaust leak cause a loss of power and/or a misfire? I thought these things were simple enough that the engine computer wouldn't be able to try and compensate for an exhaust leak, but maybe I'm wrong.

Sounds like you have two different problems. The exhaust issue could be caused by on overly lean condition. I'd tighten the bolts and check that the EGR is not hung open, and there are no intake vacuum leaks.

Reading for the O2 sensor could be off with a manifold leak.

Any codes from the CEL?