I've tried searching for an answer both online and here. Just wanted to get that out in the open before I get pestered about it.

I recently bought a 1998 Ram 1500 with a 5.9. I drove it home, all was great for a few weeks and overall, I've been impressed.

I recently began getting a misfire code. When going up long hills, the truck will stutter (and sometimes shake really hard), the CEL will flash and I'll get the P0301 code on my scanner. When I back off a bit, the light will either stay solid or just go away completely. Around town, the truck acts as it should. At idle, I can feel a little shake -- nothing huge -- but a little shake. A week or so ago, it was stuttering while idling. Always get the same P0301 cyl one code.

I recently had a hole in the cat manifold (the bracket that holds it up snapped off with age and gave be a pretty big hole). I replaced the whole cat, as it was easier and seemingly cheaper. I also installed a cold air intake. Sometime around the cold air intake install, I began getting this problem. The truck always pinged, but never gave codes or misfired.

I've replaced plugs, wires, distributor cap and rotor already with no avail. I noticed there's a TSB (18-48-98) about routing of the wires. I'm going to try that at some point.

I checked the cylinder one fuel injector with an ohm-meter, but just got some jumping of the values. It would jump up to the 20's and then settle on 0. I need to check in the daytime, and compare with other cylinders to get an idea of how to "correctly" measure -- I followed guides but might be slipping up or something.

Any insight or advice would be appreciated. I'm running in circles trying to figure out the problem. I've heard it could be the layout of the plug wires, or a throttle positioning sensor, or even a crankshaft position sensor.

 

I'm fighting the same issue... you should get 11 to 13 ohms on that injector.. could be what you mentioned and also head or ring issues..what does the plug look like? fouled, wet ,dry?

 

Have you fixed the plenum yet?

 

Not sure if plenum was fixed. I bought it a few months ago Gonna go check the injectors again.

Sounds weird, but could it be a switch to synthetic oil? Ran great till I did the change, which was oil, filter, cold air intake.

 

None of those should have anything to do with it. If it is just one cylinder, need to have a close look at it. Verify the injector works correctly, then check compression.

 

How do I check compression?

 

Need a gauge.

 

You can get inexpensive compression testers from any parts store. Harbor Freight has them for around $10 on sale-normally they're around $30 most places. They have a dial gauge and number of hoses designed to screw into the spark plug holes. They say the best way to test is to mark all your plug wires for the cylinder they came out of and remove all spark plugs and disconnect the coil wire from the cap. Screw the correct hose for the plug threads in the head into the spark plug hole and crank the engine-4-5 times. Check the dial gauge and it should be between 130-145 lbs. If you have a plenum leak, the cylinder, in theory, should leak compression and not be as high as the rest of the cylinders. A couple caveats: 1) Worn rings can cause low compression. 2) Carbon on the valves can cause low compression. 3) A cracked head or blown head gasket can cause low compression. So using the compression tester is a step in diagnosing the plenum issue, not a definitive, single test.

 

I'll give this a try this weekend. I'll try to find a cheap one on Amazon (I can get it here tomorrow) or take a trip to the parts store.

I *might* have solved the issue. When I installed the CAI, I don't remember removing the negative battery lead. Could not resetting the computer cause my issues? I ran the truck up the same hill that was giving me trouble, and it did fine. Went up and down ten times, flooring it at times, with overdrive on and off. No ping and no stutter. No codes, either. Idle even seems cleaner.

 

My Husband did a top end rebuild on my 1997 Dodge Ram but mine is a 5.2 and ever since he has done it it don't have no power and it act's like it's Miss firing but we have tried compression testing and replaced the crank sensor and it still has the same problem and will not come up with a code. We have shut dont cyl. with the computer and everyting it coming back fine but it don't run right.