Noticed a few months ago the missing or off/on throttle and it only happened with cruise set. I don't drive the truck much but when I do I've noticed it does this intermittently. I drove the truck 600 miles this week back and forth to work and cruise worked great...today back to the bad behavior, except for the first time it happened with cruise turned off. At one point I pulled over the truck was bucking so bad and took a look at everything, never tried to die, idles fine. Tonight I scanned for codes and only got P0602,which I've seen many times before. My fuel pressure is always steady at 17 psi during this. I have a Blue Chip upgraded VP44 almost 1 yr old and 5k miles.

As I understand it the 2002 cruise control is not vacuum controlled. How does the ECM control the speed? I know the APPS should throw a code if it's not right.

We're hooking up the TT on Wed morning to head to Port Aransas, but acting like it did today gets me in gear to get this fixed. I've got Sat and Sun to troubleshoot then order any parts and ship overnight.

First thing tomorrow I will unhook batteries clean all grounds then reset APPS, new fuel filter, any other ideas?? Anybody got a schematic of how the cruise is wired?

 

On the 6spd trucks, the cruise is electronic.

If you have a surging problem and it goes away when you engage the cruise, it's almost a guarantee that the APPS is on the way out. This is because the APPS is taken out of the loop when the cruise is engaged.

Your truck is almost identical to mine and I had a similar problem only it didn't do it with the cruise on. An APPS reset might send you in a direction to look further but I personally would lean towards the APPS. Has the APPS ever been changed or is it the original to the truck?

I've put 2 Mopar replacements and 1 Timbo APPS on mine in 200,000+ miles. So far the Timbo is the mileage leader of all of them.

Jeff

 

Until yesterday, it only happened with cruise on...not all the time but at least 80%. Turn off cruise, then truck would run normal. Now it does it intermittent cruise on or off. After some reading I'm cleaning every ground connection, bought new batteries, and shielding the wire that runs over the alternator. New fuel filter also. I think I'll order a new APPS on Monday to have shipped overnight just to be safe.

If anybody has been down this same road, please tell me how you fixed it.

 

I don't know about missing, but surging, in cruise, can be from your combo of Catcher ECM and bigger injectors. Just over correcting and going to far when it tried to maintain speed.... followed by backing off.
My Smarty does this on higher settings.

RJ

 

you could always try the apps reset. but if you need to buy I would buy timbo's apps, vice the very high dollar oem.... i think Timbo's around 160$ oem is what. 400-600$

 

Solved!!! Just got back from a trip pulling my 37 ft TT (11,500 lbs) and not one miss or any issues. I was desperate to fix this before the trip since it became a major issue not just on cruise but pretty much wondered if the truck would make it home the Friday evening that I started this thread. I read where someone had cleaned all the grounds, new batteries and shielded the ground running over the alternator and fixed it. My batteries were 5 yrs old and although the truck started fine in the summer, I noticed in the 15 deg cold we had this winter it was very slow to crank. I bought new batteries, cleaned the cable connections very well with new bolts, removed all grounds on the engine block and body and sanded or wire wheeled to bare metal, shielded the wire crossing the alternator. I drove the truck ~50 miles on that Sunday and never experienced a miss with cruise on or off. I went ahead and ordered a new APPS from Blue Chip Diesel on Monday to arrive on Tues...installed and left out Wed morning. I've driven about 800 miles and all is well!!

I'm convinced that the batteries and grounds were the issue, since the APPS almost always sets a code. Since it was the original APPS I thought it wise to replace it also. Since I just installed a Blue Chip VP44 not long ago, I didn't suspect that either. If I were someone who didn't do all my repairs and had to rely on taking the truck to a shop, my symptoms could be diagnosed as dead pedal and VP44 replacement or the APPS needs to be replaced, or both at a very high expense. Either way, it just goes to show how important simple clean voltage is on these electronic controlled diesel trucks. I will always keep my batteries in good shape and clean connections now!!