2000 3.5 V6 HELP

[fourwd1]

Cracked head at cyl #3 at only 37K mi. It's out of warranty so a local shop with a very good rep replaced the head. They had some problem setting timing until they found the TSB on timing belt. BUT, now it has a flashing CEL, code is mis-fire cyl #4 - lean (not the replaced head, the other side they didn't touch). Also Random Mis-fire code at times.

They reset the timing belt numerous times, swapped plug, coil,and even injector between cylinders but error stays at #4.

They're at their wits end, anyone have an idea ?

Thanks.

[Zaphod]

Whoa! Slow down, sparky!

IIRC, the Trooper has a 60K mile warranty on the drivetrain for subsequent owners, so that shouldn't be a problem.

Did they replace the plugs with factory originals? If they used Bosche Platinums, you WILL get a CEL for misfire.

Link for the plugs: www.sparkplugs.com/results_app.asp?AAIA=1363272&mfid=3

The only reason I've heard for a flashing CEL is a bad head gasket, and even then it's iffy.

[fourwd1]

The time is up on the warranty, I don't drive it everyday.

No, they used Champions and NGKs. I told them about that this morning, they're getting some.

CEL flashes only when I you are on the gas pedal, even a little. Stops when no pressure on the pedal.

Head gasket is new ( along with the head ).

Thanks.

Any more ideas, anyone ?

[Zaphod]

I know exactly what your light is behaving like. I've had the same problem. Annoying as all getout. Others have reported the same problem, but normally it goes away once the engine is stopped for about a minute then restarted. Head gaskets have been a leading cause.

I assume your computer isn't throwing codes? Mine never did.

[fourwd1]

Computer is giving codes,see 1st post.
Must be reset by scanner.

They are going to try Denso plugs instead of the Champions they put in.

[Zaphod]

You should be able to clear all codes simply by disconnecting your battery for 10 minutes or so.