H3 ISSUE: periodic check engine light-cylinder misfire

[WRB100]

I have read several threads about misfire issues and find that most have certain critical differences and several different solutions. I would like to ask you all what you would do at this point of my issue.

Vehicle: 2006 H3

Engine: 3.5L 5 cylinder

Vehicle miles: 92,000

Occurrence One: Check Engine light appeared and scan tool stated a misfire in cylinder 2.

Steps taken: I changed the original spark plugs making sure to replace with AC Delco Iridium plugs. I also switched around the coil packs between cylinder 1 and cylinder 2.


Occurrence Two: After several hundred miles later the Check Engine light appeared and scan tool stated a "random" misfire. No particular cylinder.

Steps taken: Delivered to GM dealer for check up and they scanned the engine. Reported to me the two occurrences of error codes. Told me they cleaned the throttle body and tested. Nothing more to do.



Occurrence Three: After three weeks away from dealer and about 1000 miles later, I have received another Check Engine light. I have not attached a scanner yet, but can only assume it will be a misfire since it appeared at idle just like the other occurrences. What steps would you take at this point?

Replace cylinder 1 Coil Pack?

Return to dealer?

Or something else?

Frankly, I do not trust this particular dealer. For one, during the duration they had the vehicle they told me they wanted to change the spark plugs because they were original. I promptly told them I changed the plugs already. So, I caught them in a lie. I live in South East Michigan (Metro Detroit area) and would like to possibly get a recommendation of someone local who really knows these engines and will give me an "honest" and educated survey of this engine and issue at hand if that is the consensus to take to a mechanic. Either way, I intend on keeping this vehicle for a while and would like to find a professional that will treat me right.

I appreciate any help any of you have to give and thanks in advance.

WRB100

 

[alrock]

What codes are you getting? If you provide the numeric code we can provide better responses. I'm assuming #1 was P0302 and #2 was P0300. Is that correct? If so, run the codes to see what #3 is. There's a big difference between a P0300 and a P030x (where x = 1 to 5) when it comes to troubleshooting.

 

[TAPDH3T]

I can't wait to see the answer on this.. I have the same issue and I'm only at 40k miles.. I have changed all to same plugs and am still seeing the same error code on cylinder 7! Truck idols rough as well.. I know I need to clean the throttle body..

 

[Renagade132]

How about changing the coil pack on one like you suggested, and see if that solves the problem. I have a feeling it is.

 

[WRB100]

First occurrence was P0302. Second occurrence was P0300. I am working on getting the current code. My close friend owns the scan tool so I need to make time to get to his place and kook it up.

 

[Best4x4]

TAPD, might wanna change your spark plug wires. On my Alpha I had an OEM plug wire that just wouldn't stay fully seated. I'd either hear it sparking or the CEL would come on. I just used the higher $$ brand from Oreilly's and I never had another issue. Or just check em to make sure they're all fully seated (especially if you did any work under the hood near them).

 

[deserth3]

What kind of shape are your battery and battery terminals in? That will cause weird things to happen. I'd consider this first.
2nd is consider a bad head. It was an 06 problem. Most would go bad by 25k. Some took longer. The Colorado got their head covered through 150 k miles. H3 has been ignored. So You may need to do some complaining.
3rd is leaking exhaust manifold. But i don't think that's throwing codes for most people.
Also find a dealer or mechanic you feel you can trust. Any GM dealer can work on the H3. They just need a competent Mechanic

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[Pappibri]

I guess it depends on where you have taken it to. Cadillac of Novi and Suburban Cadillac of Lansing were both Hummer dealers years ago. I have used both, but actually prefer Suburban Cadillac in Lansing. Novi Cadillac would be closer to you.

 

[08H3]

I fought with that a couple years ago. I honestly can't remember if it was a particular cylinder or random, but it was ultimately a loose intake manifold. Good luck tracking it down. Mine about drove me nuts.

 

[WRB100]

I fought with that a couple years ago. I honestly can't remember if it was a particular cylinder or random, but it was ultimately a loose intake manifold. Good luck tracking it down. Mine about drove me nuts.

What part of the manifold was loose and how would that cause a misfire? Aren't misfires basically electrical?

I am thinking about changing to a new coil pack unless someone convinces me otherwise. Of course the further I go into this the more it costs. Grrrr.

Frustrating to say the least. I had this same engine in my 2004 Colorado and NEVER had issues like this.

 

[Happy Hummer]

Ok.....lol.
Let's take it from the top.

*1 replace spark plugs (oem)
*2 replace all coils
*3 replace battery & terminal connectors
*4 clean TB inside and out (proper tb spray)
*5 clean MAF (proper cleaner is maf spray)
*6 all injector replaced (tighten bolts on intake manifold)

No order to list but way cheaper then stealer ship.

Chris

 

[TAPDH3T]

These are what I'm getting.. I will get new boots tonight to see how that helps.. If not I will start with what's on the list...

 

[TAPDH3T]

Welp I just replaced the spark plug boots with the Bosch lift time warranty boots.. As of right now no more engine code..

 

[TAPDH3T]

Error code came back still showing misfire in cylinder 7!!! I'm getting angry

 

[chaos254]

Error code came back still showing misfire in cylinder 7!!! I'm getting angry

DTC P0207

• Injector 7 Control Circuit

This is a code for the #7 injector not spark plug or coil. Check for any chafed/damaged wires by the injectors. Here are some tests you can perform if you have a noid light. I bought a noid light kit(works on multiple makes and models) when I was having no start issues with my mustang. Worked great and allowed me to determine if the fuel injectors were getting a signal.


Circuit/System Testing

1. Ignition OFF, disconnect the affected fuel injector harness connector at the fuel injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal A and ground.

¤	If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test or replace the fuel injector.

1. Connect the J 34730-405 between the control circuit terminal B and the ignition 1 voltage circuit terminal A.
2. Command the fuel injector ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

¤	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the engine control module (ECM).
¤	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

1. If all circuits test normal, test or replace the fuel injector.

Component Testing

Important: The engine coolant temperature (ECT) sensor must be between 10-32°C (50-90°F) for an accurate measurement.

Measure for 11-14 ohms of resistance between the terminals of the fuel injector.

If the resistance is not within the specified range, replace the fuel injector.

 

[TAPDH3T]

Welp I found the problem.. I found that one of the wires right at the female plug was broken.. I couldn't tell because the codent was holding it together.. I little manipulation and it fell right off.. I got a GM plug from a buddy who recently replaced his injectors and the check engine light went away immediatly...

 

[4speedfunk]

Weather-Pak. There's enough to know about em, that its worthy of a college course. Glad you found the issue.