I have a 90 iroc 5.7 with the speed density system. My problem comes when I take off from an idle there is a hesitation. Sometimes it is worse that other times, but it does not happen all of the time. As a matter of fact if I drive my car all day it might happen twice. Also don't know if this has anything to do with it but it has a miss as well. But with the miss it does not miss all of the time. I can't even tell going down the road but at an idle I can feel it. Now I have changed all the common tune-up commponents but other than that don't know where to start. I have done searches and have read other post but nothing like this has come up. Could it be TPS, EGR, injectors??????

COULD SOMEONE PLEASE HELP!!!!!!!!

 

Try check the EGR valve. If its still the orignal then its definitely time to replace it. Maybe a tune as well would do wonders for your engine.

 

Could be fuel related to. Either pluged injectors or a failing fuel pump.

 

Try replacing your fuel filter, also do you have the correct gap on your spark plugs? Theirs really a ton of things it could be. What all have you replaced?

 

You did the simple tune up, plugs, wires, dist compon., fuel filter, pvc, air, oil. Did you then set the TPS and IAC? You did read through the FAQ right? Checked out all our cool stuff (shameless plug, yes I know). I would start there in order to have the basics covered and out of the way.