As it says the engine stumbles at WOT above 45-50 mph continues till I let up on the peddle. If I slowly accelerate no problems runs smooth up to 75+ on highway. I had been getting a check engine light for 4 months or so but not all the time. It would come and go, with this issue no cel appears.

I'm still not ready for the new engine and no matter this issue has to be fixed as it will follow to the new engine as well. Could it be one of the sensors cam, throttle, crank of fuel delivery? Idea's of where I should start on this for a possible fix?

 

Have you checked your fuel pressure?

 

Have you checked to see what the code is?

 

At WOT the PCM goes into open loop. The PCM relies on inputs from ther CPS, ECT, IAT, MAP, TPS, and the camshaft position sensor, but not the O2S'.

I think your TPS is not agreeing with the MAP in this case and at WOT the fuel injectors are leaning out. You can see when you feather the throttle it somewhat acts okay, and it's in closed loop so the O2S' are helping control the fuel injector band width, maintaining an adequate rich mixture.

My thoughts are that you should check the TPS sweep using and analog Ohmmeter to see if there is a dead spot. And check the TPS closed/WOT voltages using a digital voltmeter.

This is a start.

 

I have several codes stored and have cleared them 3 different times. When the CEL comes back on and they are checked again most all will be different from what the others were. The exceptions have twice it was shown a problem with # 1/3 cyd's not firing. The last time it was a different set of cyd's not firing and that was it. Rather vague that could have been a lot of different things causing that.

This is a difficult problem for me to post online and expect anyone to understand what I can't get a grip on myself with the changing codes.

t-cell....I will check it this morning when I go out to the shop it I have all the fittings here I need thanks.

CCken.....Just pulled my DMM out of my drawer here in my radio shack that I use for amateur radio repair, a Fluke and check it right off the bat. I had forgotten how to check that sensor for function using a DMM.

Finally found my analog MM hadn't used it for a while.

Thanks guys!!