Okay. I have been working on a Chevy S10 for about 3 years off and on and can NOT figure out why it keeps dying after about 2700 rpm. Starts a little hard and usually takes 2 tries but always starts and runs. Sounds fine when idling but when you give it gas it stumble s and dies after about 2700 rpm. Was throwing a po300 misfire code. Replaced spark plugs, plug wires, distributor cap, rotor button and camshaft position sensor. Still does same thing. Cut catalytic converter off in case it was plugged. Nope. All I did was make it louder. Replaced pcv valve. Nope. Took off egr valve and inspected it. Didn't look full of carbon. Replaced maf sensor. Checked all vacuum lines with spray bottle of water for leaks. Nope. Checked throttle body exhaust pipes that led to maf sensor for cracks. Nope. Checked coolant for oil to indicate blown head gasket. Nope. Swapped gas in tank out for fresh gas, replaced fuel filter. Nope. Checked fuel pressure with gauge and was normal psi at idle. Checked O2 sensors. Nope. What is even left for it to be? Coil packs? I can drive around very slowly but when it gets past about 2700 rpm the truck just stumbles hard and if I give it more gas it dies completely. I thought coil packs threw a code but maybe not every time and also maybe not when it's not a constant misfire. Doesn't misfire at idle but it does misfire then die if you give it enough gas. Replaced fuel pressure regulator as well and checked fuel pump relay. Nope. Took each plug wire off distributor cap AT IDLE and they were all arcing.

Anybody have any ideas? Do you think it needs a new coil pack? I have asked every mechanic I know and can't figure out this damn S10.

 

A P0300 is common with a 2.2 L as coil packs go bad fairly often, and they don't throw a cylinder code. I'd be looking to replace it soon.