Under very light throttle, i can feel the engine 'hunting' (just noticable surging), and under full throttle and above say, 2500rpm the engine starts missing, cutting in & out, violently surging, and not even really accelerating. All the while the tach is going nuts (the rpm rapidly flickers up and down). Its idling a little low, going slowly up and down around 500-600rpm.

All the grounds seem ok, and the car mostly drives fine under part throttle, but feels a little 'rich' (that might be me though).

It's almost certainly electrical. Assuming the grounds are ok, would it be the distributor or perhaps the coil causing the wot issues?? Or the ignition module??

Thanks, appreciate the help!

Chris

 

The RPM flicker is a dead give away for the ignition module or pickup coil.


One thing you might try is to disconnect the EST connector and try to run it. That will fix the timing at 10 degrees. If the car still does it, module or pickup coil. If it runs more smoothly, could be module or the quality of the signal from the ecm.


good luck.

 

Thanks for the reply. What is the EST you are referring to? Electronic Spark... something?

 

If it's the ignition control module, i believe and have read on here, that the ACDelco one is the one to get.
Any opinions on that?

 

yeah, it sound like the coil pickup

 

I just fitted an ACDelco module so hopefully that'll be it. I have a new coil coming too just in case.
Thanks for the input fellas

 

I had a problem like that, I had just installed new spark plug wires, but the number 2 wire somehow fell off while I was driving a few days later. The car would not accelerate at all, the rpm needle flicked up and down all the time and the car had a serious ticking noise coming from it. I'm not saying that was your problem, but it is something that could be common.

 

Yeah i'll check that. The prob is intermittent so its hard to track. Just fitted a new ingition module and a Mallory coil, all good so far.