'88 7.3 won't idle, why, why ??

[NativeMaineah]

Hello All,

My most favorite off all my older Ford truck is killing me!

It is: 1988 Ford F-450 7.3 IDI manual shift, standard cab, dually rear and the prettiest black color you will ever see.

It's been running like a clock for years and I take great pride in keeping it serviced regularly.

Suddenly about a month ago when you take your foot off the fuel pedal it stalls. It doesn't matter if it's been running for ten minutes or ten hours.

What's really strange is when this started happening it was intermittent, drive a couple of hours and clutch for a light and it stalled. As the weeks have gone by it has only gotten worst.

The first thing I thought was either the low pressure pump and when it wasn't that i defaulted to the high pressure pump. The second it stalls I just turn the key and it starts right back up so the fuel is there.

It doesn't spit or sputter when it stalls - it acts more like you just turned the key off! I had our garage guy check it out to make sure it wasn't electrical - he admits not to being a diesel guy but the electric all checks out.

The fuel filter was changed about 300 miles ago and we checked it for water or wax build-up - nothing!

What are we missing? There must be a point where we can put a pressure gauge on the high pump and check the exact pressure - right? What is the exact pressure that pump should be putting out?

I'm grasping at straws at this point - I don't think it's about fuel pressure but I have no clue what else it could be - what do you guys think?

After dealing with this for about five weeks I can't see clearly now - likely it something simple but I'm just missing it - HELP PLEASE

Ted Sr
NativeMaineah