A few months ago I bought a Dodge van and it runs great aside from every once in a while. The temperature gauge will go all the way up and then all the way down.

When this happens, it runs terrible and feels like it's shifting funny. After a few minutes, it levels back out and runs fine. When it's acting up like this, I can hardly get it to start and it seems like it's idling really high. The last few times I have messed with it I have noticed When I unplugged the PCM and plug it back in it runs fine. The next few times I drive it. Any suggestions is that a computer issue or sensors? I have replaced countless sensors. I could not name them all right now, but I have replaced probably 10 so far and it has not solved the problem. When I unplug the computer and plug it back in the check engine light goes back off for a while and about the time it comes back on is when I start having my issues. In the last week or so it has gotten far worse. I bought a multimeter, but really don’t know where to start or even how to check possible electric issues.

 

What codes are you getting?

If the temp gauge starts acting funny and then it starts running bad.... I would be lookin' hard at the coolant temp sensor....

 

that was one of the sensors that had been replaced. That’s not the only thing that acts weird though. My cruise control light says it’s on overdrive turns off. If I turn the van off for a little while, it runs fine again. I also did notice I have made it stall before by jiggling the wiring harnesses that go into the PCM.

 

The codes that come up are for a bunch of sensors. O2 sensor throttle position sensor. About 10 codes pop up when this happens.

QUOTE=nws1990;3590794]that was one of the
sensors that had been replaced. That’s not the only thing that acts weird though. My cruise control light says it’s on overdrive turns off. If I turn the van off for a little while, it runs fine again. I also did notice I have made it stall before by jiggling the wiring harnesses that go into the PCM.[/QUOTE]

 

You have a short in the 5 volt circuit somewhere, likely on the feed side, as most of the sensor use the same 5 volt feed, as does the cruise control switches.

 

might sound like a really dumb question but where should I begin checking? This is my first time really having to deal with electrical problems. I can do pretty much anything else. Electrical frustrates the hell out of me.

 

Electrical CAN be a lot of fun.... (for certain values of 'fun'.....) I made the mistake of letting my service manager find out I was pretty good with electrical..... and ended up getting stuck with way too many odd electrical problems.... That was back in the 90's though. Thinks have gotten significantly more complicated since then.

5 volt circuit is always hot with ignition on. Check a couple sensors, see if they are getting that five volt feed, and that it IS right in the neighborhood of five volts.

 

OK awesome. I will check it out the next opportunity I get. It’s my daily driver so it’s pretty nerve-racking. It will run perfectly fine for a while and then all of a sudden, all of this starts to happen. It’s frustrating as hell to the point where it will stall out and have a hard time starting.

 

I had an issue with the 5 volt line going to the cam position sensor. The rear most manifold bolt had rubbed through the insulation on the wire where the wiring loom angles downward. It had been messed with before and was missing the factory protection. Might want to start there and then go to the o2 sensor wires as they get melted sometimes.

 

OK, thanks. I will definitely check that out. It’s pretty frustrating. It runs like a brand new van until it doesn’t. It’s been hell to try to figure out where to even start with this thing.