I traded for a 1994 powerstroke, ran great for a few days. Now upon cold starts, especially in the morning, the truck will start fine, run a few seconds and then start missing really bad. Then it stalls and you have to crank and crank like it ran out of fuel, then it'll start and stall and start and stall and eventually stay running but miss and not take fuel and smoke either blue or white. Truck has new injector harnesses. It doesn't do it when you plug it in. Also, it smells like its burning rich on the exhaust. It's a 1996 California engine running on a 1994 pcm too. Could that be the problem? It only has 149,000 miles on it. Any help would be greatly appreciated.

 

Cali trucks have different injectors and different tuning. Also sounds like you may have bad glow plugs and/or glow plug relay. If it starts fine and doesn't do it when you plug it in, that is a tell tale sign of glow plug or relay issues.

 

I just put glow plugs and a relay in it...

 

Maybe a tuning issue with the injectors and the '94 PCM.

 

I would recheck the wiring. If it starts well with it plugged up it is he rally a sign that the glow plugs/relay are not working correctly. Try jumping the relay and see if that helps the starting process.
What brand of plugs and relay did you use?
After it warms up, does it have any issues?

 

Already tried it. No change....

 

New symptoms: when going down the interstate (70 mph) it starts dropping power, smoking blue or white, and decelerating down to around 45 to 50 mph before taking off again. It started that 2 days ago, now it does it at all speeds. Its like the fuel is being cut off from it. Sometimes it drops down to 1,100-1200 rpms on the tach and wont take any more fuel than that.

 

Have you noticed if it does it differently going uphill or down?

 

Have you checked the fuel pressure?

 

That's next on my list.

 

It's the same either way.

 

I got it taken care of. Changed fuel filter, put an air filter in it (it didn't have one) and topped off the oil and now it runs great.