Ok so 85 gt 2.8 fiero, i finally got it back on the road with the new ga brakes and s10 blazer mc car stops on the dime and i love it, but here is the main issue. When i im driving doing normal driving it kinda has a slight hez when i give light throttle and when i give actual full 3/4 throttle skips amd back fires like a mofo. First thing i thought was spark problem so i did a full tune up plugs ac delco rt42s, ac delco cap and rotor and 8mm ignition wires. Thought the hez would go away but highly mistaken, now i know it has nothing to do with timing cause i never pulled the dizzy out. Im gonna put a new fuel filter in tomorrow hoping this will fix the problem but have a feeling its not gonna what else could be wrong car only has 130,000 miles and i run 10w30 in it if that matters

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[This message has been edited by IMSA GT (edited 09-29-2013).]

Check your timing. Even if you havent messed with your dist. It sounds like your timing is off
Edit to add...hesitation could be air fuel issue but backfiring sounds like timing issue. Check that before u throw more parts at it.

[This message has been edited by DLCLK87GT (edited 09-28-2013).]

Yea changed the fuel filter and seemed like it helped out alot

I hope that your fuel filter changes everything for you to the point that you are satisfied. I fought with mine for a long time because it wasn't 'just right'. I found a few things:

Check timing first. Set it to the right static advance regardless of how the car runs (10 degrees I believe).

Once timing is set, if it still isn't running right, check other things. Two culprits that I have found (and seem to be quite common) and the IAC valve (which breaks easily if over tightened) and old brittle vacuum lines.

On my car I did it backwards. After throwing a bunch of components at it I had the dealer check and my distributor plate was cracked and not getting a good ground. The dealer installed a new distributor, but they set the static timing so the car 'ran well' instead of what it was supposed to do. Caused me a lot of headache as I checked everything else because the timing was for sure set right by the dealer. Moral of the story, always check your timing, and set it to what it is supposed to be.

I did all that undertaking... did, to no avail. It turned out to be bad vacuum lines. If I knew then, what I know now, etc., etc., I would have checked the vacuum lines first and saved a ton of time and expense.
Hope your Fiero is back to normal soon!!
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