2006 Sierra 2500HD
We were towing a travel trailer; had driven 300 miles, no problem, then all of a sudden we lose tow power, no throttle effect, otherwise engine is still running fine.
We changed air filter and drove for another 1000 miles without a problem; then same thing.
At this time we had a "lift pump" installed with promises that our problem was solved.
Drove 70 miles, did it again; kept driving but top speed was around 45 mph. After about 5 miles, we took it out of tow/haul mode and it started working correctly again.
Please help!
Thanks.
