Dodge Ram v8 360 running issue

[MuleShack]

I got an 01' ram 2500 that I dont drive a lot and just had the crank sensor replaced.

WHen I start the truck up it starts right away, but keeps a high idol (say 1400) until it is running for about 10 minutes then it goes down to 600.

When I go to drive it cold, I can go down the road for a little while, but when I get up to highway speed, it seems like the engine is dying for short periods. Way more intense than a simple misfire, but it is in rapid succession and it seems like the truck is going to choke itself out, but then after it gets warm or about 5 minutes later it runs just fine.

If i let it idol in the driveway for 10 minutes then it doesn't do it at all.

Obviously it has somethign to do with a connection or sensor heating up and working better but what would cause this?

If it starts fine and idols fine then it shouldn't be the plugs or wires or distributor or coil right? All of these parts are relatively new last year with little miles on them with the exception of the coil.

What controls the idol speed that it wants to run at 14-1500rmp when started?

What sensor would be (its almost like it is) shorting out when the truck is running cold but yet work fine once it gets warm?

Thanks for any help in this matter.

[Jeremy airjer W]

I would like to see the live data from a scan tool before I made any guesses. Things like TPS, IAC, O2 data, Coolant temp, Etc. One of those would likely give a clue as to what was going on.

[Big Buck Buster]

From what you are describing, sounds like the typical TPS problem.

Let us know what you find out.

[MuleShack]

I have an Acrton hand scanner and plugged that in today and took it for a ride. The truck started fine and idled high at first and then settled down pretty quick this time. I started out and as soon as i got up to cruising speed it started to shutter and sputter where the crank shaft and U joints were chattering from the sudden loss of power and then sudden jolt from getting that power back again. The check engine light went on and blinked and then with in 5 miles everything went back to normal. I had read the codes on the scanner and there were 10 of them...one for every cylinder mis firing and then a P0300 for multiple/random cylinder misfires and i think the last one was a P0320 for a random/dist misfire and something that had an acronym of CIS or something.

I didn't think to read the other codes at the time, but after it stopped, i pulled over and shut the truck off to clear the codes and the check engine light went off. I started out again and then read the codes again and it said no codes all pass. at this time i tried to read teh other stuff like the 02 sensor etc most said OK and a few said Inc or NA.

After 5 miles it runs like a charm, but it sucks gas like it was beer.

[fishhuntwork]

How about a vacuum leak or I would say tps

[B K'S DAD]

It's a dodge,what more do you need to know?

[516]

it sounds like the tps or your fuel pressure regulator is starting to go or your fuel pump is going out.

sounds like a nice truck you have and good thing its not a ford they circled the problem on the front of the truck to tell you to leave it on the lot.

[B K'S DAD]

I had the same problem whith my Gmc but the shop never could find the problem.

[mikesm37]

had a similiar promblem wuth a saturn,I know different beast but was the temp,coolant sensor shorting out

[Big Buck Buster]

had a similiar promblem wuth a saturn,I know different beast but was the temp,coolant sensor shorting out

This is another good one. I had a chevy do the almost the same. When it was cold/but on a warm day, it would run real rough, and smell rich. I watched the temp with key on engine off. The temp read -34. After it warmed up, it went to normal.

If you have datastream on your scanner, check the temp reading with key on/engine off to see what it is. It should read real close to the outside temp. If it reads 0 or below, there is your problem.

[Big Buck Buster]

it sounds like the tps or your fuel pressure regulator is starting to go or your fuel pump is going out.

sounds like a nice truck you have and good thing its not a ford they circled the problem on the front of the truck to tell you to leave it on the lot.

Not the pressure reg. They are part of the fuel pump assembly in the tank.

[MuleShack]

Thanks for the ideas,

I'll check into those two options next week when I get a chance to work on it.

[MuleShack]

I drove it around tonight and only got 1 code while it was acting up.

P1390 Something about a control ignition system (CIS) Is this something that is spendy if it needs fixin?

The thermostat and the throttle position sensors sound cheaper so i'll start there.

[Big Buck Buster]

I drove it around tonight and only got 1 code while it was acting up.

P1390 Something about a control ignition system (CIS) Is this something that is spendy if it needs fixin?

The thermostat and the throttle position sensors sound cheaper so i'll start there.

Check the wiring harness on top, and back of the intake for wires rubbed through. I have had many Dodges that had wiring rubbing through and causing all kinds of drive-ability issues.

[MuleShack]

Well heres a positive update:

I went to parts store to get the TPS and a Temp sensor and installed the TPS and went to pull the temp sensor and they gave me the wrong part...it was too small.

So I put the air cleaner back on and hoped for the best.

Took it for a test drive after sitting for 4 hours and the idol is normal and best of all NO stuttering or clunking. I was showing 8.4 mpg on the digital read out before, but now on this 30 mile trip it was up to 13.1 mpg. Sure seem funny how one little part can cause so much problems and cause the excess fuel usage.

Before changing out the TPS, I had found a helpful topic on the dodge forum where you turn the key on (with out starting) and wait for all the lights and bells to go off. Then slowly press the gas pedal to the floor and slowly let it back up again, then turn the key off. Then start it again. After I did this routine with the old TPS, it did fix the fast idol issue but being I already had the new one, I swapped it out.

[MuleShack]

Originally Posted By: mikesm37

had a similiar promblem wuth a saturn,I know different beast but was the temp,coolant sensor shorting out

This is another good one. I had a chevy do the almost the same. When it was cold/but on a warm day, it would run real rough, and smell rich. I watched the temp with key on engine off. The temp read -34. After it warmed up, it went to normal.

If you have datastream on your scanner, check the temp reading with key on/engine off to see what it is. It should read real close to the outside temp. If it reads 0 or below, there is your problem.

I have not worked on the truck nor driven it for a week or so now. The TPS did correct the problem for a little while, then I changed the plugs and it still grumbles a little during the warm up but not much. I am going to change the coolant/temp sensor but cant seem to find it. I have heard that it is down between the alternator and the AC compressor where the coolant line runs into/outof the motor where the thermostat is. I cant see any wires down there that would hook up to the sensor. Does anyone have a diagram handy that would show where this sensor is? What is the easiest way to get at it? Or do I need to remove the alternator to see it?

Thanks again.

[Jeremy airjer W]

Remove the alternator and it will be right there by the outlet pipe. Its threaded into the intake manifold

[MuleShack]

This is getting to be a real pain.

Thanks for all the help so far.

I have replaced the TPS, then changed out all the plugs and put wraps over all the plug wires. I just changed out the coolant sensor and I still get a misfire like grumbling when the truck is in the warm up phase going down the road. Once the temp gauge hits the warm mark it doesn't do it anymore and the truck runs fine.

With the changes I have done so far I went from 7.5 mpg to around 11.5 (avg with city and hwy). When I check for codes during the warm up period when it is misfiring, all I get now is a P1391 (Manufacturer Control iginition system or Misfire). The O2 sensor says INC and the Egr says NA, not sure if that would have an effect. Is the Control ignition system part of the PCM? Would that need to be flashed?

This is typically what happens when I try to fix stuff by myself, I make some repairs and then it turns out to be something else that I cant do or cant find.

[Big Buck Buster]

Does your scanner show just the codes, or can you read Data too? If you can read Data, check for misfire data. This might be under "memory resets" in the catagory section where you would select codes,data,etc. If you can select "memory resets", you will see on the next page where it says misfire counters, reset addaptives,etc. Select misfire counters, now it will tell you how many misfires are counted on each cylinder. Now you can narrow down to what cylinder is causing the misfire.

Hope this helps.

[MuleShack]

Doesnt have that, just has the read codes option and then a MIL option and a screen that lists some things like 02 sensor, EGR sensor and it the options are either OK, NA or INC.

[Jeremy airjer W]

You think a intake belly pan gasket leak could cause these symptoms? When you changed the plugs where the back plugs really fouled? more than the other plugs?

[Big Buck Buster]

Doesnt have that, just has the read codes option and then a MIL option and a screen that lists some things like 02 sensor, EGR sensor and it the options are either OK, NA or INC.

Darn, that would have made it a little easier.

[MuleShack]

The plugs were a little "worn" but nothing that made me think fouled, and I didn't notice any real color differences when replacing.

I suppose I could redo the distributor for S & Gl's, but not sure that is the problem either.

The only thing that improved by replacing the 3 things listed was that previously it grumbled and stumbled where its abrupt hesitation would be really jerky in the truck. Now it is like the choke is on where if i try to floor it, there is no response and it seems more like a misfire with just intermittent sputtering.

[fishhuntwork]

I think I said a vacuum leak a while ago. Take some carb cleaner and spray around intake bet it starts to run better.

[MuleShack]

Finally got around to taking this thing in to dealer because I couldn't figure it out. They replaced cam sensor because there was a communication problem between the cam and crank sensor. They fixed and then said next progression was issue with crank sensor. I had that replaced at another place in late July...not going to pay you to do it again. Finally took it to the original place and they checked it out and turns out the crank sensor was faulty, cutting out every 3rd revolution. They are replacing under warranty and putting in a new O2 sensor so finally getting this thing up and running and will get the MPG up.

New Tranny with under 1K miles, new Cam and Crank sensors, TPS, New Coolant and oil pressure sensors, new Distributor and rotor...Good set of rubber. Now its time to sell it.