problem

[hcox10]

hi
i have a 84 h/a when i give it 1/3 of throtle it runs great but when i give it wot it starts to miss it does not backfire it just misses couid that be maf or coil oxegin sensor or what. i have a fuel gauge on it. it reads 42 at wot.so i do not think it is fuel.
thanks for your help harold

 

[ngianop]

If you're sure fuel delivery isn't the problem and the ECM isn't showing any codes, check the ignition system; plug wires, coil, coil module, etc. There's info on this site to walk you through diagnostics. Don't forget to confirm TPS setting, good MAF, injectors, etc. If the ignition system is original, the coil or coil module could be suspect. Ensure that electrical system (e.g., battery, alt., ground leads) is healthy too. Others on this forum may have other ideas. Good luck.

 

[RegalT-type85]

agree with above, also check your Spark plug wires for grounding.

 

[hcox10]

hi
forgot to say the car runs great w.o.t until it warms up then it starts missing
thanks harold

 

[Waco84GN]

You say the car has 42psi at wot? If so I don't believe that is enough. That is around base fuel pressure. Either your pump is not strong enough to push more pressure or the fuel pressure regulator is not doing it's job.

The fuel pressure reg. should have a vacuum line going to it as well. The fuel pressure should go up 1 psi for every pound of boost you build.

Check your vacuum line to the regulator.

You could be leaning your car out under boost and possibly damaging your motor.

Just my thoughts.

Jerry jr.

 

[BRAD_PADGETT]

hi
forgot to say the car runs great w.o.t until it warms up then it starts missing
thanks harold

I would start by swapping out the coil module. Brad