2000 S40 - Ignition Issues

[AGSchear]

Hi all,

I posted a few months back about some issues with my 2000 S40. I'm still having some trouble but can offer some more and more specific information now about the problem. Hopefully someone will be able to help me out!

The trouble, I believe, is somewhere in the ignition system. I have a CEL giving me the code P0303 - misfire on cylinder 3.

Corroded spark plugs have been replaced with properly gapped new ones. Not OEM but I seriously doubt they're the problem.
Brittle ignition coils and spark plug wires have been replaced with OEM parts. The car definitely gained some HP but didn't solve the problem, which has become very repeatable now, so I'm very confident it can be solved.

Here's the issue: When I start the car, it takes 5 to 8 seconds to turn over. The RPM's quiver, almost to the point where the car stalls, then the come back to somewhere between 0.7 and 1, which seems normal to me, and remain stable. Sometimes the RPM's are on the high end of that range and the car rattles a fair amount (probably due to that misfire), sometimes the RPM's are on the low end of that range and the car is smooth. Either way, it blows a small puff of white smoke out the tail pipe right at the start, after taking a bit to turn over. Smells like gasoline. At no other time does the car blow smoke.

Now, if I turn the car off, right then and there (or after any driving), then go ahead and turn it right back on a second later; it starts up perfectly. No smoke, no gasoline smell, almost always less rattle, no RPM quivers. Just a smooth, clean start, like it was brand new. This is what I expected to have when I bought new plugs, wires, and coils.

I checked the PCV valve by feeling where the oil dipstick goes. Seemed fine.
Oil level is good. I use regular gasoline, and have for the past 25k miles with no issues until the past 1 or 2k.

I realize I may have overlooked some suggestions in my old thread, if you were a part of it there, but thought it would be helpful to have a new one with updated information. If some of those still apply, let me know em still!

Thanks very much in advance.

[jimmy57]

Your symptoms listed now sound like an injector (#3 since it has that code) is dripping fuel and flooding cylinder 3 when engine is off.

[elchopperfreak]

Would give the IAC a good clean as well...
Heres a link
http://www.30forty50.com/forum/topic/72 ... valve-iac/