1995 Dodge Ram 1500 5.9 - rough engine above 2000 RPM

[95DR1500V8360]

Hello.

I have a 1995 Dodge Ram 1500 V8-360 5.9 Liter.

It has been working fine up until last week. I had just left, driving down the road and it started to falter, sputter and lose power above 2000 RPM. I brought it back and started to diagnose the problem.

The fuel pressure stays steady at 40 PSI, it doesn't change at all at idle or acceleration. There may be a fuel pressure regulator, I have not checked. All the components of the fuel system (filter, pump) are one unit in the tank and I have not replaced that yet, I am hoping I do not have to do that.

I just replaced the crankshaft position sensor because that is apparently a common problem, but it did not solve the issue.

Compression is consistent for all cylinders at about 115-125 PSI.

No oil in the throttle body, not likely a gasket issue, no burning (or at least not much) of oil. My levels are not changing.

No codes. It has an OBD 1 (not 2) - no codes present and no check engine light.

I have not pulled the injectors yet.

Pulled the connector to the O2 sensor on the catalytic converter, no change. I also "banged" on the catalytic converter - no noise potentially indicating it is not a problem with the catalytic converter.

The truck will idle at about 900-1000 and be fine for about 5 minutes until it warms up. OR if I try to increase the RPMs (even after just starting it) the engine will start to run very rough and start to stall above 2000 RPM.

I did have a similar problem a couple years ago when I was near empty and I barely had enough power to move forward. I limped to the gas station, filled it up and it was happy. I currently have 1/4 of a tank so I don't think it is the same problem, although I did add some seafoam to the tank. I also had a cylinder misfire on my newer Chrysler van that turned out to be a bad/clogged fuel injector, but that was only affecting one cylinder, this seems to be affecting all cylinders.

This post is similar to "225365-engine-runs-rough-at-2500rpm-and-starts-to-die-at-3000-rpm.html"

I would appreciate any suggestions on what to look at next. Thanks.

 

[RamRod37]

My first thought is cam sensor in the distributor had this on a few or worn distributor shaft bearing causing movement but only above 2k rpm's may be hard to get a definitive result

How To Test The Camshaft Position Sensor (1992-1995 5.2L, 5.9L Dodge Ram Pickup)

Symptoms Of A Bad Camshaft Position (CMP) Sensor. Circuit Descriptions. TEST 1: Testing The Camshaft Position Signal. 1992, 1993 5.2L Dodge D150, D250, W150, W250 Pickup. 1994, 1995 Ram 1500 Pickup, Ram 2500 Pickup, Ram 3500 Pickup.

troubleshootmyvehicle.com

 

[95DR1500V8360]

Thanks RamRod37. Interesting article, I will test that later today/tomorrow and see what it says. Any other thoughts?

 

[95DR1500V8360]

Sorry for the great delay in responding but I did find the problem. Another forum suggested I remove the cat O2 upstream sensor (located inside the cat); I did and the truck could breathe again and ran fine.

I removed the exhaust system, cut off the pipes from the cat and everything inside was busted. (Although when I banged on it, there was no rattling of broken pieces inside)

Unfortunately it is an expensive replacement so I will be purchasing a new cat for the truck shortly.

Strangely enough, the new cat's are half the size of the current cat. Everyone tells me this isn't a problem, but it seems to me there would be an air flow restriction due to the small size. We will find out soon enough.

Thanks for all the help!