Canadian Hummer Club Forums

I have a 2003 H2 I bought in April of this year. She has 103K on her.



When I looked at her I took her in to the only certified Hummer shop in Ottawa. It turned out this H2 was originally bought at this dealership and was serviced there as well.



She came with a clean bill of health and all services were done on their respective schedule. I was told the only thing remaining was to do plugs and wires.



Yes I have been procrastinating getting that done.



Recently I have been experiencing a rough idle plus an anything but smooth acceleration. I am going to take that as my clue to get off my butt and get the wires and plugs changed but was wondering if there should be something else I should also be looking at that may be causing the rough idling and acceleration.



So I am stopped at a light. It is kind of a thump feeling in idle, like a shake. On acceleration it really does feel like I am only getting spark every 3rd or 4th time, very much what you would think bad plugs would feel like.



However, could it also be something else?



Thanks in advance



J.Carroll

​Do you have any codes ? I would do the plugs, and even though the mileage is low . I would clean the injectors and throttle body . If you have codes , it could be throttle position sensor or mass air flow .



​Heck it could be a bad battery connection or battery . I am no H2 expert but i think what you are describing with the H2 . Theses are possible causes for your issue . I am sure the H2 guys and Polar Bear will way in . Good luck bro

Our 2003 H2s have a fuel filter, start there! If you haven't done a tune up yet, this should be your next step. I highly recommend NGK iridium plugs and a Good high performance wire, Taylor, MSD, etc. Also check your air filter, it may seriously need a cleaning/replacing! You should change your PCV valve to a traditional style the orifice type are junk and can be the cause of it by itself!



Hope this helps,



Kev

So I had made an appointment for plugs and wires. The night before my appointment she ran real rough and the engine light came on. Next day I dropped her off and asked to run the scan to see why the engine light was on.



of course they called me and told me I needed new plugs and wires. Should have stayed with my instinct and saved the scanning charge but at least I knew for sure.



Both fuel filter and air filter are new from the spring.



She runs nice now.

To any H3 Alpha's reading this topic try cleaning throttle body but first check the oil level with the dip stick Rhino was shorted oil on an oil change and ran rough till he was topped up. ( note even dealers can short the amount of oil especially on the Q8 engines like the 5.3 v8 in the alpha H3's which use engine oil to lock the valve lifters turning on and off cylinders as needed)