Canadian Hummer Club Forums

I was driving up the 400 hwy and noticed that when climbing hills at 120kmh I would loose power. I had jus got an oil change done before my trip. Can anybody give me an idea of why this could happen. As it has drove great before oil change.

I had a loss of power due to vacuum pump failure. Might also be your fuel pickup is plugging up with crud, could be alot of things

If I'm driving at a lower speed like 90-100kmh while climbing hill then floor the gas it would give me the extra power. But if I'm driving 120-130. And floor gas it won't give me anything more and still loose speed. It nvr done this before. Anybody have or know of a good shop for h2's. Is there any issues with transmission that could cause this issue. I'm located in mississauga

If you floor it from 90-100km/h can you get over 120-130km/h? Or does it block up at that speed anyways?

Is your truck speed limited or have the tires been changed and the speedo has not been recalibrated?

Do you have any codes?

Is the check engine flashing?

Thanks,

Kev

It's blocks up at 120 and if I'm lucky it will gradually go up to 130. But this is only on hills. If I'm on flat road it will move fine. No codes or light on. Tires were changed when I got the truck with same size that was on it. This issue only came right after oil change. Truck is not speed limited that I know of.

Ok, next set of questions;

1. Does your RPM increase going up a hill but just no speed increase?

2. Was the transmission oil changed at the same time as the engine oil?

3. Have you checked the condition of you engine oil and transmission oil since the oil change was done?

Thanks,

Kev

Oil looked nice and clean not black before oil change was done. Tranny oil not changed yet but looks bright red. I'm planning on changing trans oil soon


My rpms don't jump at all when I floor it at 120-130 it jus slugs along at same rpms.

If I'm on flat road and punch it at 120-130 rpm will jump and truck will move. Only have problem on hill.