I was towing my jeep this weekend and my truck acted up 2 or 3 times. I would lose power and have to come to a stop. I had my pocket scanner with me. It showed p0300, p0131, and p0151. I believe it also backfired once. I've also had issues with it idling only when in drive/reverse but not in n/p. Not sure if this is related. Thanks for help in advance.

99 Silverado 2500 6.0

 

Ttt bump

 

We had a GMC that came in few months ago.. it was a firefighting rig that ran the nastiest fuel those guys could find. it misfired, ran horrible, pretty much what your describing. i got misfire codes and that was it. i tried plugs and wires and the back cylinders were super fowled. ended up being a fuel pressure regulator that fixed the problem, they tend to be a common failure on these trucks.

 

also check your 02 sensors.. those codes lead to sensor failure.. which id bet my money on.

 

I've already checked fuel pressure and it seems the fpr is working fine. Would one bad o2 sensor cause both codes?

 

Bad 02 sensor would cause these issues.

 

The first oxygen sensor closest to the motor is having a issue. Check the connections. That sensor failed and is causing the issues you at having.

 

It has 2 upstream o2 sensors. How do I determine which is bad?

 

Anyone?

 

Bump again.....................................