Car breaks up under WOT between 4-5500 rpms

[slodsm92]

Just recently had head gaskets, head studs, timing belt, w/p and all pulleys done. 92 1g laser with intake and turbo back exhaust for mods. I noticed recently while driving into higher rims (4500 and higher) it breaks up, back fires, trips a check engine light. As soon as let off the check engine light turns off and the car drives just fine again in lower rims (4500 and lower). Everything looks connected correctly. Any ideas on what it could be and where to start looking? Thanks for reading.

 

[pauleyman]

any recent tune up activity? How many miles since that work? Mechanical timing could be suspect. Does it idle and part throttle drive EXACTLY as it did before? It should not be better or worse after a belt job. It should be identical.

 

[jdxnc]

First steps are to closely inspect plugs and wires for any signs of damage, if nothing is visible, gap the plugs a little tighter and see if it fixes it. If it does, likely the plug wires are shot or have a small spot where they are arcing out somewhere under load, considering they were recently removed and reinstalled, they can be damaged quite easily.

 

[slodsm92]

any recent tune up activity? How many miles since that work? Mechanical timing could be suspect. Does it idle and part throttle drive EXACTLY as it did before? It should not be better or worse after a belt job. It should be identical.

It starts, idles and runs perfect until wot 4/5500 rpms. I normally shift gears between 3/4000 rpms and you would never know there's an issue. Ill check plugs and wires tomorrow

any recent tune up activity? How many miles since that work? Mechanical timing could be suspect. Does it idle and part throttle drive EXACTLY as it did before? It should not be better or worse after a belt job. It should be identical.

It's maybe a 1000 miles since work was done.

 

[pauleyman]

It starts, idles and runs perfect until wot 4/5500 rpms. I normally shift gears between 3/4000 rpms and you would never know there's an issue. Ill check plugs and wires tomorrow

Arcing on plug boots is hard to spot sometimes. Look for small white dots.

 

[99dsmer4g63]

Sounds like you are blowing out your spark. New plugs gapped tighter.

-Daniel

 

[diambo4life]

What's the CEL for?

 

[Justin DuBois]

Just recently had head gaskets, head studs, timing belt, w/p and all pulleys done. 92 1g laser with intake and turbo back exhaust for mods. I noticed recently while driving into higher rims (4500 and higher) it breaks up, back fires, trips a check engine light. As soon as let off the check engine light turns off and the car drives just fine again in lower rims (4500 and lower). Everything looks connected correctly. Any ideas on what it could be and where to start looking? Thanks for reading.

Are you running ECM Link? The "Dash" tab has features that will turn on the check engine light.

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