Runs on 4 cylinders--

[power-stroker]

I own a 2000 F250 6spd 4X4 extended cab. I bought in new and put 105K miles on it. I have had this problem before. The forum sugested to change the valve cover gaskets which I did and it quit, for a while. This was about two years ago. It is doing it again!! What I have learned is that when I first start it, it runs on all eight. Shortly after, it acts up. All 4 right side cylinders do not fire. When it first started acting up, I could wiggle the plug on the valve cover and it would run on 8 again. I have the stick, if I turn off the ignition while going down the road and turn it back on it will run on 8 for a mile or so and then act-up again.
I removed the right valve cover, cleaned and pinched all the connectors, washed the conectors off with a q-tip with alcohol and put it back together. I took it for a 15 mile ride yesterday after putting it back together. I pushed it pretty hard and it never acted up. Today I went to start it and within 1 minute it acted up again. I pulled the right plug off while it was running (on the left side)and plugged it back in to no avail.

Any Ideas!!!

[mschn99]

the valve cover gaskets arent the problem usually for this concern.....its the wiring harness under the valve cover that plugs into them...the connectors sag and the they start to slide out and disconnect themselves...

[power-stroker]

Ok!! The plugs were all plugged in all the way. I didn't notice anywhere the wires were touching. Should I replace the harness under the valvecover? Thanks

[fordmt]

The replacement UVC harnesses come with a small plastic tang molded into the connector which maintains upward pressure on the latch so it doesn't unplug from the VC gasket interface.

Mike Cleary

[power-stroker]

Ok thanks! What kind of a job is it to replace the harness and how much$ for the kit.

[Dave]

Originally Posted by power-stroker

Ok thanks! What kind of a job is it to replace the harness and how much$ for the kit.

Dont know the cost on the kit but you pull the valve covers unplug the old harness and replace with the new one

[mjurecki]

i have the same problem but none on the drivers side will fire. i've had the problem before about 5-6 months ago but that was becuase an injector was shorting out and taking the whole bank out.i've unplugged every injector one at a time on the drivers side and can't get one to fire. i've got it running and pushed and wiggled every connection and still can't get any to fire. is there a way to test to see if its the wiring. my SES light is on. i've taken it to advance auto and there scanner wasn't able to scan it so i order the AutoEnginuity but that won't be in till jan 3.

[pipelayerjdh]

You could try swapping the valve cover gaskets from one bank to the other. If they start firing, get new gaskets and under valve cover harnesses. If they don't, you may have a harness problem.

[fordmt]

Originally Posted by mjurecki

i have the same problem but none on the drivers side will fire. i've had the problem before about 5-6 months ago but that was becuase an injector was shorting out and taking the whole bank out.i've unplugged every injector one at a time on the drivers side and can't get one to fire. i've got it running and pushed and wiggled every connection and still can't get any to fire. is there a way to test to see if its the wiring. my SES light is on. i've taken it to advance auto and there scanner wasn't able to scan it so i order the AutoEnginuity but that won't be in till jan 3.

It's possible that you have an IDM failure on that bank---when you get the AE, see if you have a code P1284.

[fordmt]

Originally Posted by power-stroker

Ok thanks! What kind of a job is it to replace the harness and how much$ for the kit.

I think they run about $85