my friend has a 93 fd and at idle in neutral when the fan kicks on the engine surges between 800-3000 rpms erratically.anyone have any ideas where to look or have a similar problem?any info woul be greatly appreciated. thanks,cliff

 

what ECU are you using? Could be fuel correction map for battery voltage is wack

 

it is running a m2 comp.

 

Could be bad grounds.

 

thats what i was guessing as a suspect.how do i find out where or should i try running a ground strap from the engine?any ideas?

 

im pretty sur eits a vacuum leak b/c pretty much the same hting happened ot me. it would also surge badly when my lights were on.

 

i have the same problem except the problem only occurs when my headlights are up and when im in gear trying to drive..im still trying to diagnose the problem..ill let you know if i find anything..

 

el load system prob. shity iac, poor alt performance