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westcoast 01-29-2011 03:41 PM

Won't idle
My 1999 4.7 over heated. I flushed the system and refilled. It is now idling very rough and dies! It seems to run ok going the road.
Any ideas?

Scottina06 01-29-2011 04:05 PM

Sorry bro....ya warped the heads prolly

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Crispy 01-29-2011 04:26 PM

Re: Won't idle
Good chance that you did warp the heads. How long was it driven while overheated? Did you find the cause to it overheating? Need more info to try and help you out.

westcoast 01-29-2011 04:33 PM

Re: Won't idle
I'm pretty sure I didn't warp the head. After changing the water in the radiator I did not know to bleed the system so it got a little hot but I was right there working on it so when it started to get hot i shut it off. After bleeding the system it started right up and I can drive it but it will not idle. Do you think it could be the collant temp sensor? Maybe to got hot and is messed up!

Frango100 01-29-2011 06:37 PM

Re: Won't idle
These 4.7 engines really don't like to be overheated. Not removing the bleed screw will leave a large amount of air in the system and can cause heat damage very quickly. You don't have your check engine light on? Its possible that you blew your head gasket. Any signs of air bubbles in the cooling liquid expansion reservoir?
The PCM uses the coolant temp sensor for several calculations, but not sure if a broken sensor would make it unable to idle. Just disconnect the sensor and see what happens.

westcoast 01-29-2011 07:34 PM

Re: Won't idle
The check engine light is on now!

Scottina06 01-29-2011 09:15 PM

Re: Won't idle
do the key dance and pull the code or have the code pulled

westcoast 01-30-2011 07:50 AM

Re: Won't idle
Code P0308

Frango100 01-30-2011 08:44 AM

Re: Won't idle
Cilinder 8 misfire detected. Maybe best to do a compression check on all cilinders to see how that looks. But after an engine overheat, there is a big change of head warp or headgasket problems.

Scottina06 01-30-2011 09:23 AM

Re: Won't idle
yep...pull that plug and do a cooling system pressure test.....sounds like a blown gasket and maybe a slightly warped head. Could be as small as a pin leak or pin holes in the head right around the #8 cylinder

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