Won't run cold

[Sierra Mike]

I have a '96 F-350 4x4 with 370K miles and it will not run properly when the engine is cold.

After initial starting, it will idle fine. However, if I do not let it warm up for about 10 minutes or so (depending on the outside temp), it will start to bog down and lose power from second gear on - the colder the engine, the earlier the gear it will start to bog.

It starts out fine, but generally will suddenly start slowing down in speed somewhere above 30 mph, and the engine RPMs will slow down. If I apply more throttle, it will bog, puff white smoke from the exhaust, lose speed and RPMs faster, and likely stop running. If it does not stop running and I pull over, it runs as though only firing on some of the cylinders. If it dies, it is very difficult to start and will run very rough until it warms up.

Any ideas?

[Sierra Mike]

Yeah, well it has me stumped too!

[DonF350]

You use fuel treatment?

[Sierra Mike]

Originally Posted by DonF350

You use fuel treatment?

I do not use fuel treatment. The problem only occurs when the engine in cold, otherwise the truck runs awesome and gets near 20 mpg.

[jesilvas]

Unplug the EBPV and see if that fixes it.

[DonF350]

Does it have that problem when you have it plugged in

[elrojo63]

unplug the Ebpv and check your valve cover wiring harnesses and make sure one isn't loose. Will it eventually idle perfectly?

[Sierra Mike]

Originally Posted by jesilvas

Unplug the EBPV and see if that fixes it.

This did not fix it.

Originally Posted by DonF350

Does it have that problem when you have it plugged in

No. If it the block is warm (either by keeping it plugged in, or by previous running) the problem does not occur.

Originally Posted by elrojo63

unplug the Ebpv and check your valve cover wiring harnesses and make sure one isn't loose. Will it eventually idle perfectly?

All of the connections seem fine. It idles perfectly upon start up, or if the block is already warm. The problem only occurs when I attempt to drive when the block is cold.

[Sierra Mike]

Well, now it is gonna be off to the mechanic for $75 per hour. I cannot figure it out.

[away]

I had a 95 in my shop this week with the same problems.

CPS-cam position sensor fixed it.