Still trying to figure this out.

I did a couple other things to try and isolate the issue, but I don't know if it is significant.

First, try as I might the 02 sensor isn't coming out easily. I replaced it 9 years ago, so I know it isn't the age of the truck, but its not new either.

Crank position sensor only has 1 of the 2 bolts holding it in place. I remember years back the shadetree guy I had install the motor said that the one from the original swap was cracked somewhere, but he stuck it in the hole and everything fired up fine and it didn't seem to be an issue for 10 years.

I've noticed than when idling, there are pufts of smoke coming from the tailpipe...not thick enough to say for sure its not white, but I think its grey smoke. I'm thinking we are running rich?


I wanted to isolate which cylinder is misfiring, so I went to pulling plug wires off to determine what is firing. This is what I don't understand; it runs just about the same with 8 pulled off the plug. It runs just about the same with 4 pulled off (that's the cylinder with the 100 psi compression). It runs just about the same with 4 and 8 both off. It will even run with 2, 4 and 8 off...all dead.

I put them all back on and then went to pull #3 off the drivers side bank, and it runs a little worse, but will even run that way. I wouldn't think I could get a healthy engine to do that. What does it mean?

 

Disable IAC (just unplug it) and try again. The PCM will see the RPM drop when you disable a cylinder, and try and compensate for it.....

 

I'm back....got fed up with sensors for a while, so I have been daily driving my 69 caddy, but my wife wants me to clean out the storage shed, so, time to get the Ram back.

We previously did some trouble shooting to try and eliminate the plenum problem. We were thinking it might have been ok, and were looking at sensors. I decided I wanted to find out what was going on and put hands on it. I hooked up a vac gauge while running, and it flitters between 10-15 hg at idle. Valves, maybe? That fluctuation made me think more mechanical.

I took off the valve covers, and at least they all look to my eye, not totally wrong. Nothing is extremely loose, no hardcore damage, a few I can wiggle but I guess that's cause they are totally closed. I also have taken off the serpentine belt to feel for play with the timing set, maybe I can move the crank pulley a half inch before it tries to bring the cam along.

So, off comes the intake manifold, just because I can. I have found about 1-2 shot glasses of smooth, not grimey, dark oil in the intake. I don't think it came through the pcv system. Is that enough to confirm that I do have a plenum leak?

 

That sure sounds like a blown plenum gasket. It would also explain the bouncy (and low) vacuum.

 

You've got the intake off, you should take the plate off and put a new gasket on it anyway. Then you'll see what the old one looked like. I would change the timing set and water pump while you have it that far apart.

 

Back again, still wrassling this issue.

I redid the plenum new timing chain and crank sensor to go along with the O2 sensor and the new cap rotor and wires that I had done previously.

It's still suffering from the same problem. It almost sounds like the timings way retarded or something, sort of a flat blubbery sound at idle. I don't have a good ear though.

I'm running out of things that can be I guess. Camshaft sensor? It's running very very poorly, and when they problem arose I just driven 150 miles and then all of a sudden I realized that when I slow down in overdrive it was wanting to die. I haven't tested fuel pressure but it sure seems like there's a good little stream when I tap the Schrader valve.

 

Really need to test pressure with a gauge.

What brand crank sensor?

 

If the engine runs okay when it's cold and the problem comes on as it warms up, then your evap system may be your problem as well. Is this is so, try running down the road with the gas cap off and see if the engine runs better.

 

It's an O'Reilly sensor (masterpro), ...I know mopar is preferred, but it runs exactly the same with this sensor as it did with the last. What are the chances that both are failing, same exact way...and with no codes? I don't believe it's the crank sensor.

It runs bad cold or warm.

 

Time to do some data logging, and see what the PCM thinks is going on.