Hello all,
I have a 2004 Chevy Trailblazer LS 6 cylinder 4.2 with 138k miles on it that developed a misfire in cylinder #4.
I thoroughly cleaned the throttle body....still a misfire.
I changed all plugs, fuel filter, air filter, checked all coils...still a misfire.
I swapped the plug & coil from #4 to other cylinders & had it re-tested...still misfire in #4.
Used fuel injector cleaner...still misfire in #4.
After all of these steps...I did a computer re-set by disconnecting the battery terminals & using my jumper cables to connect the cables for 30-45 minutes.
Am I right in thinking the problem HAS to be either electrical or compression? What should my next step be on a budget?
Thanks in advance!
physically check for spark (see FAQ)
checked for spark....that is fine....
I'm thinking this is an electrical problem: my auto start key fob stopped working, & it drains the key fob battery every 36 hours.....I think maybe I need to replace the wiring harness to the coil packs? Does anyone know the OEM of this harness??????
if you're getting spark, then the coil packs and harnesses are fine.
Swap injector with known good cylinder.
Why don't you stop throwing expensive parts at the problem, get it scanned for a diagnosis and repair that which needs it?
Do the compression test on that cylinder.
bought the compression tester....that is well within parameters......checked for spark....that is fine....
I'm thinking this is an electrical problem: my auto start key fob stopped working, & it drains the key fob battery every 36 hours.....I think maybe I need to replace the wiring harness to the coil packs? Does anyone know the OEM of this harness??????