Hello:

I'm new here - living temporarily in the US - from Germany

My '97 Tahoe 4x4 5.7l with about 110000 miles is behaving weird mostly at about 70 mph - rpm is jumping down and up again and again, control lamps like anti-lock and engine service soon are coming up and go away... the car is shaking like hell...

Since I experienced continuously loose contacts at the battery poles - I changed the terminals from that factory screw-on thing and changed to stud-clamps and put in a new battery (2 weeks ago), the issue seamed resolved, but today again at highway speed it did start to stutter, not that heavy but also connected with blinking lamps in the instrument panel. I missed to check the voltmeter.

My guess is, there's another bad contact maybe a ground cable...

Just once, before I changed the terminals (I had the most serious stutter)
I got the "engine service soon" light staying on and had to delete a code - it was a MAP sensor related code - that was a non-recurring exception.

Is there any comparable experience or ideas how to narrow the root cause?

Thanks in advance - Jens

 

Welcome to the forum.

I'd check all ground connections and then fuel pressure for starters. Others here may have some more suggestions.

 

Might also be arcing or cross-firing from plug wires, check routing and condition of the wires, higher humidity can make it worse (read rainy days).....

 

Hey guys - thanks a lot!
Have to do some home work now