Thanks, already ordered the Camshaft Solenoid. Hopefully that will be it. Ill keep you guys posted.

 

I was having problems with multiple misfires. The engine would hesitate, stumble, idle real rough, almost stall, no power. I replaced all the coils,plugs,injectors ( injectors helped a little), intake gasket valve cover gasket, and still had the problems.
I found this forum thru the search function on this page ( seems like some people dont know its there), and decided to try replacing the camshaft soleniod.
Called the local GM dealer and they had the part in stock for $58. I had ordered new camshaft sensors (both intake and exhaust side) days earlier and they arrived the same day.
picked up the part, put them all in and right away i noticed a drastic difference in the engine. Driving it around for a little bit improved it even further.
the only problem now is I am still getting a CEL and the code is saying "cylinder 3 misfire". the truck is running 90% better. it's not perfectly smooth at idle all the time but is a major improvment then before.
Will this get better and go away as i drive it more? Or is there somthing else that i should replace?

 

Now you have a cylinder specific misfire. Recheck the plug, coil, and injector on #3. Visual inspection on the coil and plug, or swap the coil and plug with another cylinder to check if the misfire moves to another cylinder. Use a mechanics stethoscope, while engine is running to listen to the injector on the #3 (you can listen to another injector too, so you know how it should sound). Recheck the connectors to the #3 coil and #3 injector. If all checks out, check compression on cylinder #3. GL

 

I also replace the camshaft solenoid and cleaned out the throttle body and changed the spark plugs. I did notice a difference also as I drove but I still get some misfires and my car shuts off sometimes when I come up to stops. I did get the code p0017. Any idea what could it be? I put the camshaft right.

 

so i pulled the plug from 3 & 4, to compare them. 3 was significatly darker then 4
was.
mind you all these plugs are less then 6 months old. same goes for the coil packs. in fact #3 was replaced again a week ago with a oem coil pack.
i also dueched the throttle body, and maf sensor, i cleaned as much of the intake as i could . swapped the plug from 3 to 4, left the coil packs in the same spot.
It still idles rough but has not yet kicked the CEL for #3 misfire. i have only driven it 7 min to work so far but the code usually wouldnt even need that long to pop back up after deleting it. i dont have a way to listen to the injectors, but they were just replaced with oem part less then a month ago, so those should not be a problem.

 

The one thing that I did not do was clean out the MAF for some reason it slipped my mind. when i changed out the spark plugs on my H3 I noticed that the spark plugs that were in my H3 were completly different than the acdelco ones i put in there. I put originals (new) back in there.. I attached a photo of the old spark plugs.

 

Save yourself some time and avoid driveability issues, ONLY use ACDelco 41-103 (12625058) iridium spark plugs (Alpha use ACDelco 41-110 (12621258)).

 

so after some more research i decided to change out the knock sensor. even tho i didnt have a code for it i figured that it could still be acting up.
it make a big differance. after driving it for a little bit you could feel the difference. i towed a trailer with about 1200 pounds load and i had no issues with power or hesitation.
onlyafter about 1 hour of driving when i got into the city and the speeds dropped the cel blinked but never stuck on. where as before it would come on within 20 min of clearing the codes.
on my return trip it came on and stayed , so i pulled over and checked/cleared. it was throwing a code again for cylinder 3 misfire. altho i did not feel like there was a skip or hesitation.
started it up this morning and right away the cel was on, so i cleared it and drove around then to work and it is still off.
question is what is going on? obviously a new knock sensor made a difference with somthing. I can just feel that the engine is performing better. but why is cylinder 3 still misfiring?
also ever since changing the knock sensor my dummy light for "stab failed, traction control failed" has been more sparse as well, and not just by a little. it very rarely came on during the trip and when it did it went off either right away or within a few min. this is very different from it's norm. it use to come on and stay and very rarely go away, but always came right back.
just to recape what has been done in the battle to track down the cause for misfire.: all coils, plugs replaced, new intake gasket, valve cover gasket, new camshaft position sensors ( intake, exhaust side), camshaft position acuator soleniod, new knock sensor.
rough idle dramatically improved after replacing the knock sensor. it no more does it's act where it almost stalls then comes back.
am i dealing with a bad head here?

 

Don't jump to a conclusion: check compression on cylinder #3

 

My H3 is finally working again normally!!! I did everything you told me, changed the camshaft solenoid. Cleaned out the throttle body and the MAF sensor. It was still acting up. I then decided to change the oil and oil filter. The oil was completly black! I had waited to change the oil because on the service manual that I had from the record of the car the oil should have been good for another 2000 miles. That made a huge difference!!!!!!!!!! Thanks should hav echanged the oil when i changed the camshaft solenoid!! Its funny how somtimes we over look the simplest things! Thanks again!