Hi, I recently bought a 1999 Dodge Ram 1500 5.2l 2wd and it had a bad alternator so I replaced it and a buddy of mine threw a battery in there for me. After I got it running I noticed a intermittent misfire and checked the plugs and noticed cylinders 3 and 6 had messed up spark plugs so I replaced those and the wires and tried again still not much of a change. So I scanned the engine light and got a P1391, P0303, P0306, P0300 I saw that the P1391 was for intermittent crank and cam sensor so I replaced the cam sensor and no luck I still haven’t done the crank but the guy did say he did it not too long ago and I also noticed the MAF sensor was re wired but covered in electrical tape so I’m going to check that again today and try to solder that but other then that I thought if you had a bad crank sensor the car wouldn’t start at all but it still does every time I only have stalling problems randomly if I pop it in reverse.

 

Crank sensor has a variety of failure modes that will still have the engine running, just not very well. Cam sensor is only used during startup, after that, the PCM pretty much ignores it. Given you have misfires, that sounds a lot like bad crank sensor... When you replace it, ONLY use a genuine Mopar sensor. These trucks just don't play nice with aftermarket sensors in critical locations.

You have a MAP sensor.

MAP: Manifold Absolute Pressure.
MAF: Mass Air flow.

 

I’m gonna do the crank sensor today and hopefully it works thank you for the reply

 

Just FYI, I'm also experiencing a intermittently failing crank sensor (code P1391 was found after the truck's engine cut off while driving down the road). I pulled off the road and reset the computer by removing/re-installing the battery cables and the truck restarted. I was able to drive for another 20 miles or so and it ended up dying again while driving, so I reset the computer again and made it home. The crank sensor I have in the truck now is an aftermarket BWD sensor that has seemed to work fine for several years, but is now becoming intermittent and unreliable. I've ordered a MOPAR crank sensor online and hope to install it as soon as it comes in.

 

Hey I just got done replacing the crank sensor and saw that the guy before me never screwed the bolt next to the trans dip stick all the was in but I replaced it anyway and bolted it on all the way and after driving for a hour it fixed the code but now I still have a cylinder 3 misfire

 

Cool, you got that code fixed, put new plugs in it and check the wires. new plugs, go with champions, don't get fancy with them.

 

What plugs do you have in it now? How old are the cap/rotor/wires?

 

I just replaced the plug that was misfiring and redid all the plug wires I did notice a noise similar to bolts in a can and saw somewhere it could be the cats the noise is sometimes off and on and doesn’t really change with engine speed so I was wondering if that had anything to do with the misfire and sluggish feeling

 

Sounds like spark knock.... Marbles in a tin can under acceleration?

Have you checked the plenum?

 

It is like marbles in a tin can but acceleration doesn’t effect it at all and it has no rhythm. It and it randomly goes away after like 10-20min and sometimes comes back when I’m idleing and when driving