Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

P0410 and Misfire ?!?

3170 Views 5 Replies 5 Participants Last post by  Joel1
First - Thanks to everyone on the site - HUGE valuable source of information on my '04 TB

Second - About 10 months ago started getting sporadic P0410 codes usually only when it was raining (I've read TONS about this problem) Eventually the code stayed on all the time. :worried:

Discovered water in the vac line and replaced the check valve. SES light turned off ~YAY~ :woot:

At the same time did 100,000 service consisting of fuel filter, fuel induction cleaning, oil change, air filter, tranny flush, brakes, tires, rear shocks, iridium plugs (coils were in "pristine" shape according to shop so they were not changed) - Needless to say I don't really want to put more $$ into the truck especially since it is close to being paid off. If I do spend more it will be to replace the stepper motors in the cluster for the gas gauge.

A few weeks ago on our annual trip to NC the cruise stopped working. We pulled over and shut the truck off, restarted and while at idle the RPM gauge jumped up to 4,000 although the motor was not actually revving that high. I assumed it was just the stepper motor going out in that like the gas gauge did. Right after it happened the SES light came on. Pulled a random misfire code :duh:

Weren't experiencing any other problems with vehicle at all. Decided to reset code and take a couple hour rest. Started driving again and no more code, cruise working fine. :woot:

Two days after getting back home I heard the vac kick on right when I started the truck and it was making a high pitched squeeling sound that stopped when the vac kicked off. I thought maybe it was because the AC was left on full blast from the day before and the temp outside was over 100.

Next day same squeeling when starting. On the way home that night the RPM gauge did a spike again and the SES light came back on immediately. Checked codes and P0410 is back along with random misfire or 2nd cylinder misfire. It's been jumping back and forth between random and 2nd ever since.

What I am wondering is if anyone knows of a problem that would throw a P0410 as well as misfire code or is there reason to believe I am getting a false misfire code due to the RPM gauge issues.
I checked the vac line and it does not have water in it so I do not think the check valve has crapped out again. Checked plug/coil in cylinder 2 and they are also clean, dry, good to go. Not experiencing any other problems and mileage has not been impacted however I do not hear the vac kicking on anymore when I first start the truck. :sadcry:

Any help would be greatly appreciated. Really stumped.
See less See more
1 - 1 of 6 Posts
P0410 is totally separate and independent from random misfiring.

I'd suspect the relay down under the truck near the turbine air pump. But if you want to troubleshoot it scientifically with a meter, the master P0410 thread has plenty of discussion about that process.
1 - 1 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.