The culprit- 98 Dodge 3500 van 5.9 with 190,00 miles.

Gremlins- intermittent rough idle, mega skipping, shuts off, engine light, multiple misfire codes,downsteam o2 sensor codes,crank sensor codes- ALL INTERMITTENT! Terrible mpg and power when these are going on.

What we've done and replaced-

Compression test-good on ALL 8

Removed,checked,cleaned injectors

New O2 sensors,crank sensor,map sensor, IAC valve,plugs,wires, distributor, computer,coil,intake gaskets,cat converter and muffler. Checked all electrical connections,battery cables,etc.

All the codes are gone now but the misfire codes- random on all cylinders, no rhyme nor reason. Seems to cut off when engine temp reaches about 195-200- then will not restart- let it sit for almost 5 minutes exactly everytime- refires and runs great- (cuting off when it goes from open to close loop is our guess?) The problems have gone on randomly for 3 months, thru 3 computers. (2 used,1 new) Here's the kicker- put a 97 5.2 1500 computer on it- runs great! Still cuts off, but not as much- more power and better mpg- but no guages, speedometer,etc, and won't pass inspection of course. We are stumped and beyond frustrated. Any help? Thanks in advance!!!

Check the coil for carbon tracking near the harness connector, that is VERY common on these engines.

If it is still mounted on the engine, you might see it with a mirror while running.

I've seen bad splices (buried in the harness) cause all kinds of electrical intermittents. FSM gives approx. locations.

I have also heard of cracked t/conv drive plates that cause some ignition trigger pulses to be dropped. Never actually seen that.

Rick

we had a intermitant problem simular to yours on a 2000 dodge van, we replaced the ignition componentents, and much more, the problem still came and went.. replaced the crank,and the mudule under the cap.. still same problem. took it to the dealer. They worked on it about 1.5 hours and the van would not act up.. told them what it was doing. The Mech guess was to wait till what-ever it was go out or try the ecm.. so i bought a re-man ecm and it hasnt stoped. Thats been 2yrs ago..

We had some trucks cut out and run bad because the 5 volt wire to the dist pick-up (hall effect) was rubbing and shorting on the drivers side valve cover in the back near the firewall. Ron

Kinda sounds like the timing chain may have stretched or skipped. At 190k it needs to be done regardless.

does it have a coolant sensor, check that.

coolant sensor is next on the list. Going to check for the carbon tracking at the coil. Rick- a tech here at Crown in Greensboro mentioned the crack TC plate- says they've seen it on some trucks. We got another 98 5.9 computer that hadn't been reflashed with the "death tune" and it does better- runs with more power, better mpg, but now it's loading up at idle like a T quad with a stuck choke and sunk float-lamo- having to do the "mopar shuffle" with both feet to keep it running at idle. Other than that it's about right- engine light comes on at idle- multiple misfire code- it goes off after about 20 miles of hiway driving and stays off til it has to idle for 5 mins or more.

I know this is a broken record, but check/clean grounds! Heating up and shutting off is electrical, and with all the other stuff you have done, it does not sound like a single sensor or the PCM that you have swapped a bunch.

Also, with the ECT disconnected, it should go into open loop. Does it run okay until it goes into closed loop (easy to track with a scan tool).