Status update...

Since I had to take it in, apparently they determined the plugs were not OEM and replaced those. They also cleaned the injectors. That worked for all of 2 weeks, then the engine skip came back...not as often (to not at all), not as strong, and it didn't start until the tank was lower on fuel. Now it skips every once in a while at idle at completely random times. Could we be looking at a lose or bad wire?

 

I'm having the same issue with a rough idle on cold startup...it's goes away once the truck gets to running temp...just started doing this a few days ago..and kind of frustrating since I haven't even had the truck one month...dunno what to do, it's not throwing any codes. Should I bring it back to the Chevy dealer?

 

Found the cause in speaking with a coworker. After describing the problems he said without a doubt it was a coil pack issue. I told the stealership to check the coil packs and they "assured" me that wasn't the issue because because no codes were thrown and they were functioning normally. I strongly said to check the pack with the problem cylinder and sure enough as they moved the pack, the problem moved with it (but they assured me the packs were fine...rolls eyes).

 

Thanks for the info...trucks going in Thursday so I'll make sure to mention the coil packs..I'll update when I get it back

 

Well I took my rig into the dealer yesterday.. Just so you know its a 08 3.7. It was running rough on startup and then still idling a lil rough, but not to bad even after warmed up.. Well my head is bad so they are replacing it.. So that is what was causing my issues.. Should have it back tomorrow, will report how it runs then..

 

Just got mine back today p0301 cylinder 1 misfire was the code it threw...dealer replaced the coil pack and plug...runs like a champ...I'm glad it wasn't the head seeing how I've only had the truck about a month..but either way got the 3yr 36k warranty so I'm not too worried..an I thought head issues were mainly the 06's?

 

Mine started to have a rough idle 2 days ago, sometimes its bad and then sometimes its not bad at all but still noticeable. Took it to my personal mechanic with a scan tool and found my number 2 cylinder coil pack is misfiring. Scan tool also shows the history of all coil packs, I need to get a scan tool now. Waiting for my mechanic to give me a price of a coil pack and some new iridium plugs for my repair. On the Checker O'Reilly website shows that the coil price ranges are from $49.99 for a RPT coil to a $156.99 AC Delco OEM replacement. BTW my mileage is 109,250 miles with the original coil packs.

 

Just replaced my #2 cylinder coil pack with a AC Delco replacement and changed all plugs which were gapped to .043" Everything is running fine and the check engine light went away. Also cleaned my throttle body since I had everything off too.

 

Might be your catalytic converter I had the same problem thought it was my spark plugs, coil packs or air filter turns out after a while the converter started rattling n the start up idle got worse

 

Coil pack is a very common cause for symptom described, I purchase a whole set of coils for my H3 from autopartstomorrow last month got 12% off +free shipping, ACD D1935E (2007-2010 3.7L) @22.10 each.. Much improved idle after replacement.

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