Looking for some 348 help

Swap the coils side-to-side. Coils can be very hard to diagnose, as they are intermittent as they go bad. If it changes to 5-8, then you know. Likewise with the igniter mounted by the coil. You're lucky that it's a one-side problem from a diagnosis standpoint, as there's a seperate system for each side of the motor. You can swap many of the parts side-to-side to test for failure. Also, you can do the same with spark plug wires, as they are intermittent when failing also.

 

May be a bad O2 sensor. The universal ones are only around $60 and are common failures. Usually they are indicated by a loss of power on one side of the engine, though it is often not accompanied by the check engine light.
BT

 

You might also post this thread in the Technical Q&A section. Lots of the technically oriented people will not see it here.

BT

 

Sounds like the oxygen ("lambda") sensors.

The problem could either be a legitimate problem or a "fake" problem arising from one or more poorly connected electrical wires. Disconnecting and then reconnecting every electrical connection after the use of a cleaner (like Stabilant 22s from Ricambi America's web site) might very well solve your problem.

Do a search using this forum's search tool on "check engine" or anything else you can come up with and you'll find plenty of advice.

 

Check Engine lights *always* have a code attached. You say that you ran the manual test and nothing came up...that may mean that you tested the wrong ECU (you've got two, and they don't share codes).

So go pull the check engine code again.

Backfiring is typically due to a lean fuel mixture, though there are other causes, by the way.

 

What he said.