Scotty

iTrader: (13)

So I purchased an inexpensive 1996 SC400 with 220k miles. Car is in decent shape, but had developed a misfire while in the possession of the dealership I purchased it from (according to them). I was hoping there might be someone with a similar experience that might be able to offer a bit of advice.

Here's what happens:
-When the car is first started it runs and idles smoothly (hot or cold).
-After about 30 seconds it starts idling a bit rough.
-It also runs slightly rough when driving.
-During driving the check engine light comes on and will periodically start to flash quickly.
-The trac/trac off light also come on intermittently with the check engine light.

What I've done so far:
-Read the OBD-II code and come up with P0308 Misfire on Cylinder 8, no other codes present.
-Figured I'd go ahead and replace the plugs, and discovered a bit of moisture in the cylinder 8 well and a bit more corrosion than expected on the threaded part of the plug (probably from the dealership washing the engine). I cleaned and dried out the well and dried the plug wire.
-Put everything back together temporarily to test the new plugs and still ended up with the same result, runs smoothly at first and after a short period the slight hesitation/rough idle begins.
-Checked for spark on the plug wire to the 8th cylinder and it was good.
-Checked the distributor rotor and cap, both were in good condition.
-Swapped ignition coils and still ended up with the same result.
-Jumpered the fuel pump ECU and no change.
-Pulled the plug back out and cleaned the well again, but still no change.

So I've done a ton of reading and am still at a loss, runs smoothly for about 30 seconds then starts a rough idle and only throws a code on the one cylinder. What's odd is that I'm pretty sure this was caused by washing the engine, but everything is super dry now and still having the same problem. Is there something super obvious I'm overlooking before I move on to the Fuel injector and ECU?

Thanks,

Scotty

Scotty

iTrader: (13)

Any suggestions would be greatly appreciated. Just drove it again, made it about 2 minutes with no problems.

Scotty

iTrader: (13)

Just swapped injectors and still have a misfire on the same cylinder. I also cracked open the ECU and all caps looked fine(not that that means it's good). Not sure where to go from here. Maybe a new ECU? In driving it a bit more, it appears that the misfire subsides a bit while driving and then slowly comes back at idle.

Scotty

iTrader: (13)

I finally figured it out. It was a plug wire that was intermittently having issues, even though they looked pretty new. I should have double checked the obvious first.

SQ400

You my car just start doing the exact same thing. I changed all same parts last month and end up just being the drivers side coil. I feel crazy now of all the parts I have replaced I have yet to replace the wires and have replaced every part you listed above. Head to get wires now.

WadeLovell

iTrader: (5)

Which wires did you end up with OEM, ACCEL,...?