car ran great. mods in sig. took iot out with some friends and it has stumbled ever since under load. it's getting worse. it does it badly from a stop sign or in the higher gears. everything ignition is new. It's almost like the opti is crap already, but the car has a new waterpump and has never seen rain. opti is 2k miles old. maybe the harness is bad or the opti is crap?

 

was the water pump installed after the opti? water/coolant= kills opti.

 

no, all installed at the same time. never been exposed to anything.

 

Double check that all your spark plug boots are fully seated on the spark plugs and that you haven't burned any wires on the headers.

 

ok, i might add. This problem is not due to something stupid simple like boots being off and or burnt wires. this is the 2nd set of wires with this same problem, 3rd set of plugs. no burns in the wires or anything. what can i check to see if the opti is working??

 

Fuel filter? Kind of sounds like a fuel problem now

 

i would assume its fine since it fixes itself when i get on it hard....also dynoed fine with the problem.