2007 hummer h3, another recent problem I start to have is when I turn the car on first time lets say in the morning . it starts no problem but I hear like its stalling but its not really staling if that make sense, like I hear the engine does like dod dod dod dod and even the exhaust in the back you hear the same thing. the RPM is the same its not bouncing, and then after like 5-10 second it goes away. and it sound normal again, if I turn it off and started the car while its hot it doesn't do that its only like first time when its cold. and this all started like few days ago. no check engine light nothing.

any suggestions or help on how to fix that would be appreciated.

 

 

I don’t have that secondary air thing it’s been removed and the car been tuned without it . It just started recently , what else could it be ?

 

How many miles on the 07 H3? When was the last time you cleaned the TB and MAF (with TB cleaner and MAF cleaner respectively)?

 

roughly 130k and I did it couple weeks ago

 

Did what? Or, more precisely, what did you use to do it? If you used Carb Cleaner or Brake Cleaner we know where your issue is coming from.

 

I cleaned the throttle body with a throttle body spray cleaner made for throttle bodies

and I cleaned the maf sensor with a maf sensor spray cleaner specially for maf sensors

I did that couple weeks ago

 

did the issue happen before the cleaning or after the cleaning? maybe make sure there are no cracks in the pipe between the throttlebody and maf sensor and that the rubber on the throttlebody is seated correctly. sometimes it foldsd itself over as you remount it to the throttle body on the inderside and not visible. thats how i found mine when i origionaly purchased my truck.

 

it happened after but i always clean them regularly and even after the cleaning it was fine for like couple weeks and then all the sudden it start to do that. The only thing I did different that I just remembered is I put an oil catch can. But I don’t think that causes this.??!!

 

it might if it is letting in unmetered air into the intake that is not being registered to the maf sensor causing a lean fuel trim condition or random multiple misfire like a 300 code..