This is an intermittent problem but I feel like it is getting worse so I thought I would ask for thoughts.

This is on my 07 3.7. I have an intermittent engine surge. It is not on takeoff, but more like merging on to the interstate or even holding steady highway speeds. I can feel it and I can see the tach drop. If I give it more throttle for a minute it usually straightens it out. Whatever the problem is, it is not throwing a code. I have changed plugs (Delco), cleaned the throttle body, changed the air filter, ran several tanks with Lucas to clean the fuel system... Trying to narrow it down. Thinking MAF sensor, throttle position sensor, fuel filter, vacuum leak... Whaf do ya'll think? Anyone had this? Thanks.

 

How many miles on it?

 

Just under 99k.

 

Bad TPS.

 

Run some Techron.

Chris

 

Thanks guys! I'll try both...

 

There is no fuel filter, MAF and Throttle Position Sensors will throw a code pretty quick if on the way out, from your list I would pick vacuum leak.

Until fuel additives can pick up a wrench and buy replacement parts, I can assure you they do nothing.

You could also have a PCM problem, brain farts are hard to track down, check those connections.

 

TPS time once it goes out then you will loose power and cant drive faster than 35mph will just shut you dwn. mine did it and I had the Hummer shop replace the throttle body assy,sensors the whole shebang. Luckly was covered under warranty drives great now.

 

Please stop digging up OLD threads, not needed. Thank you for your anticipated cooperation.

Read this: https://www.hummerforums.com/forum/n...bumping-23220/

 

absolute pressure send switch possibly, I had a similar problem that was resolved at the dealers under warranty some 4 years back