2003 Dodge with the 5.9 HO and 48RE transmission. Nothing has recently changed to cause this, the truck did not do this when I first bought it. It got a Smarty tune and did this. I then flashed it back to stock and reflashed the Smarty and it fixed the issue. I should have left well enough alone, but I thought HP Tuners would be better. Since it also acted the same way with the Smarty I can't really blame the HP Tuners. This does lead me to believe it is something in the electronics/tune though.
When you set cruise the truck accelerates a couple of MPH, then slows down, then speeds back up again. It constantly varies by several MPH and can't figure out what the problem is and keeps doing it. Seems to be worse on flat ground or up hills and seems to calm down a bit doing downhill.
I have HP Tuners and have generated and flashed stock tunes back in the truck multiple times along with the performance tune for the truck. Nothing really changes, although it is a bit more sensitive with the tune because of the extra power.
I cleaned all of the grounds in the engine bay and on the batteries. I also got upgraded battery cables as the stock connector cable was failing on the ends and needed repair.
I replaced my FCA with a brand new Bosch one, no change.
I tried a restrictor in the line going to the servo, no change at first, but as I made it more of a restriction the issue had a bit longer of a delay to begin doing this, but then went back to doing the same thing.
I have an Edge insight and rail pressure seems to stay steady on it as well as following the desired in my HP Tuners Logs. I can do data logs of any parameters needed that HP Tuners can capture as well. The Edge also shows the TPS to be linear and steady as the cruise depresses and releases the accelerator pedal.
I have not replaced the servo, but it seems like this would be throwing parts at the issue for no reason - unless these are a common failure point.
Not sure what to really try next. I'll PayPal $25 to anyone that can help me in figuring this out. The only other thing I was thinking about doing was asking my local dealer to do a stock reflash on the truck to see if that remedied anything.
When you set cruise the truck accelerates a couple of MPH, then slows down, then speeds back up again. It constantly varies by several MPH and can't figure out what the problem is and keeps doing it. Seems to be worse on flat ground or up hills and seems to calm down a bit doing downhill.
I have HP Tuners and have generated and flashed stock tunes back in the truck multiple times along with the performance tune for the truck. Nothing really changes, although it is a bit more sensitive with the tune because of the extra power.
I cleaned all of the grounds in the engine bay and on the batteries. I also got upgraded battery cables as the stock connector cable was failing on the ends and needed repair.
I replaced my FCA with a brand new Bosch one, no change.
I tried a restrictor in the line going to the servo, no change at first, but as I made it more of a restriction the issue had a bit longer of a delay to begin doing this, but then went back to doing the same thing.
I have an Edge insight and rail pressure seems to stay steady on it as well as following the desired in my HP Tuners Logs. I can do data logs of any parameters needed that HP Tuners can capture as well. The Edge also shows the TPS to be linear and steady as the cruise depresses and releases the accelerator pedal.
I have not replaced the servo, but it seems like this would be throwing parts at the issue for no reason - unless these are a common failure point.
Not sure what to really try next. I'll PayPal $25 to anyone that can help me in figuring this out. The only other thing I was thinking about doing was asking my local dealer to do a stock reflash on the truck to see if that remedied anything.