does anyone remember how the old chevys would vapor lock? at ideal they ran great but when they got warm they didn't have enough power to get you down the road. this is what my 99 dodge cummins is doing. i don't even know where to start. at ideal she runs great, give fuel slowly she runs great other than that she runs like crap! anybody have any suggestion?

 

I would start by checking the free stuff.

Check fuel cap/ fuel filter housing/injector lines snug etc. Make sure you aren't sucking air or not venting the fuel tank.

Fuel pressure, vp44/ codes?

 

Ditto on sixslugs post. It sounds like you are sucking air or not moving enough fuel.

 

Thanks, i'm new to diesel as soon as i try all these i'll repost.

 

Could also be a throttle position sensor or APPS as it is know on the Cummins. There is a reset proceedure, do a search for APPS reset.

Rick

 

Chad, we wil be glad to help you with a lot of this diagnostic stuff. Help us help you though by taking a minute and filling out your signature in your user profile. Tell us things like year, and model of truck and any modifications you have made. That will really help us narrow in on things that are known to cause problems in your specific truck.
Welcome to the board, you can get and hopefully give a lot of help here.

BTW - it also helps to fill out your location in your profile. That will help us know things like whether you have to deal with really cold weather. Things like hard starting are a completely different can of worms in Texas in February than they are in Alaska in February (not that you are having starting problems, but you get the idea)

 

Also by filling out your location you may find that one of us is close by and can stop by and check it out for you.

 

Chad,
Let's not jump to the assumption that your VP44 (injection pump) is going bad yet, do the simple stuff suggested above first. If you get nowhere going down that road, the link below will take you a page on the Blue Chip Diesel site that will explain how your lift and injection pumps work and give a very good set of diagnostic procedures for fuel delivery related problems.

http://www.bluechipdiesel.com/vp44diagnostichelp.html