Originally Posted by mustninty
I'm using E3 plugs which from what I have read are great plugs for this swap and many people have used them without issue. They are ungappable. I have checked for vacuum leaks with throttle body cleaner around every part i can think of. The O2 sensor is brand new, its a bosch 02 not sure about the code. It is a 5 wire. The PCV was cleaned out and is in good condition. And yes fuse has been pulled along with battery disconnected several times. More then just the CEL, the car itself is running horribly. The car has been running very well with this setup for about 3k miles and then started running badly on its own, not after any changes.
Does it idle fine on cold starts too, or are the symptoms when hot or cold?
You could always try throwing a bottle of Red Line SI-1 system cleaner into the gas tank, if for some reason this was suddenly a bad tank of gas(contaminated with water etc?)?
Try getting some stock plugs, the correct ones, for this engine. Pull the E3 plugs(not sure which those are???) and take some pictures if they don't look brand new. Use OE p/n spark plugs and see if things change. Try re-setting the ECU(pull the backup 7.5A fuse).
IF the bad idle symptom is when cold, perhaps the Fast Idle Valve has loosened enough(mis-adjusted) enough to affect the idle during startup; fast idle?
IF it's only when the vehicle is at operating temp/hot idle then it could really be a number of things else, I suppose. Including ignition related, EVEN with the new parts as you stated.
What were the brands of the 'new' parts? Is there a warranty on them?
I know you said you made sure they 'werent broken', but did you do the check from plugs back to igniter and ignition coil to make sure it's all good? You verified not just visibly, but tested the ignition parts?