I have an 02, 3500 series, 6 speed manual transmission, with 204K miles. I just bought the truck a few weeks ago and had to put a new piston in one of the cylinders. It ran great for the first 200 miles after rebuild but today I was driving down the road and the truck started missing out. It's like I hit a sudden headwind gust and the truck slows just a little and it passes about that quickly. I know it's fueling but I just checked the fuel pump pressure earlier in the week and it's a stable 12 psi at idle and 10 psi WOT. I didn't have a pressure gage in the truck when it was acting up and I put a new fuel filter in a couple hundred miles ago. When it drops in power, I can step on the throttle and it accelerates good without hesitation. I have plenty of power when I step on the throttle but when running at a constant speed on the highway between 50-75 mph the engine will start to cut out.

I was wondering if the APPS could be dirty inside and putting a erratic signal into the ECM. I'd hate to have to replace it if it wasn't bad...$460 bucks at Autozone. Is there anyway to test one or clean one? The VP44 pump has been replaced at some time since it has a remanufactured sticker on the top but I have no idea low long ago. I'd hate to have to replace that too at $1300 but if I take it into a pump shop, how will I know they aren't just rebuilding it out of habit...since they all seem to fail eventually. Is there a test I can make?

Thanks
Rich

 

First, take it to a Cummins Service Center and have it scanned with their scanner. It will cost you, but it is worth the price.

If it turns up pump codes, do not waste your money on the Cummins supplied rebuilt pumps, but go for one from one of the premium aftermarket rebuilders that has the linered rear housing, new processor, and a new front housing with the replacement diaphragm. Any other rebuilt pump option is a total waste of your money!

 

My truck has been doing the exact same thing for about two years now, Nothing has gone wrong its just anoying. I dont know about yours but mine does it worse when the temps get below 45*

 

If you have to replace the APPS, look into a Timbo unit for 160 bucks. Its 1/3 of the cost and its a very good product that will probably exceed the original.