Hi, I am new to the forum, but have used it plenty to troubleshoot issues on my truck. I have a late model 96, Ram 1500 with 5.9L gas, 2 wd. I have replaced the spark plugs, plug wires, distributor cap, rotor, camshaft ignition pickup sensor (Replaced 2x), ignition coil and crankshaft position sensor (Replaced 2x). The truck will start, idle fine just at 1k, or right below. As soon as I step on the gas the engine starts to run rough, cough and sputters, eventually dying. I have pulled the upstream O2 sensor out before the catalytic converter with the same results. I have disconnected both upstream and downstream O2 sensors to see if that changes anything and it doesn't. Timing Chain was replaced about a year and half ago. I am at a loss and am not sure what else to check. The error codes that has been thrown is P1391. Put a can of Seafoam in with a new tank of gas to see about cleaning the lines, no change. Cleaned the throttle body. Checked the TPM and it seems fine as well.

 

 

How is fuel pressure.

 

I'll check that. Need to go grab a pressure gauge and will get that information back on here.

 

Currently doing a fuel pressure check and replacing the fuel injector o-rings. If the test reveals that the pump assembly is bad, will be dropping the tank to replace it as well. Thanks for putting me on this path.

 

You don't need to drop the tank to replace the fuel pump. What you do is remove all the bolts on the fuel tank side and loose all the other ones on the other side and jack the bed up so you can get to the fuel pump. Also put a fender cover on the rear bumper.

 

Dropped the tank. When I opened it up to remove the fuel pump assembly, I found an extra gasket laying at the bottom of the tank. Seems a previous owner had left it in the tank for fun. Had to replace the roll over valve as it was completely broken and not useable. Both fuel lines were completely hard and one of them snapped off while lowering the tank. The roll over valve return line looked like it hadn’t been hooked up in many many years. Once it was all back together for testing of new parts, the truck still had the same issue. To get the truck moved out of the driveway, I put the tank back into the truck. Let the truck run for about 5 mins at idle to warm up and before parking it, gave it a rev and it sputtered and coughed but kept running. It did this for about 45 sec to 1 min and then cleared up. Held the revs above 3k and seems to have righted itself.

In all that was replaced:
- spark plugs and wires
- distributor cap and rotor
- ignition coil
- fuel injector O-ring gaskets
- fuel pump assembly
​​​​​​- intake/return fuel lines to tank
- roll over relief assembly ​​
and 1 can of sea foam.