3.0 Misfire

[EdGe_wannabe]

We had this vehicle come in with a misfire on the #1 cylinder, so we did a complete tune-up with plugs, wires, & ingition coil. Checked fuel system, injectors, pretty much everything to cause a misfire we have checked. The only DTC's is the #1 misfire.

Any help as to why this poor 3.0 is still having a misfire? This is on a 2002, 2WD, ext cab. Thanks in advance!

Brenton

 

[rurouni20xx]

sounds like a computer issue or a synchro may be off a hair. check the sensory and make sure its all copacetic, if the synchro is a hair off itll make a misfire since it throws the timing off. id double check the timing first. what kind of plugs/wires were used?

 

[betomonroy]

Also check the CKP and the CMP.

 

[Bob Ayers]

sounds like a computer issue or a synchro may be off a hair. check the sensory and make sure its all copacetic, if the synchro is a hair off itll make a misfire since it throws the timing off. id double check the timing first. what kind of plugs/wires were used?

The CMP synchro WILL NOT throw the timing off!!! Ignition timing is controlled from the crankshaft position sensor.

Have you checked the compression on cylinder #1?

 

[EdGe_wannabe]

Compression is good, 150 psi on cylinder #1. Were gonna try a leak down test in a few & I'll get back here.

Brenton

 

[Bob Ayers]

Compression is good, 150 psi on cylinder #1. Were gonna try a leak down test in a few & I'll get back here.

Brenton

Leakdown test isn't necessary, the compression would have to be bad to cause a misfire. How did you check the injectors? The best way is to swap injectors #1, and #2 and see if the misfire moves to #2.

Next question, can you hear it misfiring at the tailpipe? I ask this to determine if the misfire is real, or a false code.......