I have an 02 Suburban 2500 with the 6.0 V8. Occasionally, when pulling my travel trailer (approx 6000 lbs) the check engine light comes on. Power seems to drop off a bit and when I check the code, I find a low fuel pressure DTC logged. It usually occurs when I am either on a long steep pull, or accelerating from a stop on a steep uphill grade. Engine rpm above 4000 rpms. Fuel pressure when checked is always good. Filter is recent and problem existed before filter change as well. Anybody experience a similar problem? Are there any known issues with the fuel pressure regulator?

 

You probably need a higher output pump.

 

What is the code specifically? I have never seen a code the says low fuel pressure on any make or model.

 

P0171. funny thing is, it doesn't happen all the time. this past trip, I pulled a looooong uphill grade no problem. Descended down the other side and shut it down while I stopped for lunch. Going back up the other side of the valley, the light came on and power dropped off slightly. I'm thinking the heat soak while I ate affected something. Also noticed sometime later that the power came back on, very suddenly. Makes me think it's not a pump or filter issue, but might be a regulator issue.

 

PO171 is lean bank 1. It does not say the fuel pressure is low. If it had low fuel pressure it would most likely also have a po174 lean bank 2. You could be looking at a vacuum leak, a bad fuel injector, dirty fuel injector, bad o2 sensor. maybe a dirty MAF sensor. Although it is very very odd that it only happens when towing. I would recommend trying some regular maintenance first. Clean the MAF sensor, clean the throttle body and have someone do a real fuel injection service not dumping something in the fuel tank. The hardest things to diagnose is one that can not easily be duplicated.