Down grade with cruise on trans bucks back

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dreich
Posts: 1
Joined: Sun Jun 03, 2012 1:50 pm

Down grade with cruise on trans bucks back

Post by dreich »

U7130
9R09
2004.5 Dodge Ram 3500 Diesel
The truck has 58000 miles on it and I'm the original owner.

I just bought the Predator and installed the performance program. Took a 140 mile trip and held it on cruise @ 59 MPH and used 5 gals. = 28 miles per gallon. Outside air temp 59-65. Was getting 22-23 with the stock system at the same speed. If I ran the truck @ 70 MPH with the stock unit I would get approx. 19 MPG. With the Predator it bumped it to 22.1 @ 70 on the return trip.

My problem is that there were a lot of up hills and down hills on I-5 in Oregon. When the truck starts down a grade (doesn't make any difference if it is an easy grade or steep) the truck starts to buck almost like when a motor is misfiring. If I press the button to disengage the cruise the bucking quits. When I get to the bottom of the grade I engage the cruise again and everything returns to normal. I tried to ignore it at first but it felt like I was going to tear the trans apart. I was not towing anything and only had a two hundred pound item in the bed of the truck.
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mikel
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RE: Down grade with cruise on trans bucks back

Post by mikel »

I cant say I recall ever hearing about htis, but we'll check it out.

can you go to options/troubleshooting/show calid and post that up please?

also, if you get a chance, see if the other tunes act the same way.

Thanks
Mike Litsch
Holley Technical Sales Manager
Diablo Tech support by phone:
561-908-0040x4
M-F 8:00 AM to 5:00 PM EST
CDH776
Posts: 9
Joined: Mon Jul 30, 2012 12:15 am

RE: Down grade with cruise on trans bucks back

Post by CDH776 »

Mine does this too. i have a 04.5 with 146k miles, so i thought it was something to do with my injectors or somthing. but now seeing someone else with the same problem now i know its not. but as soon as i take the tune off its fine.
Zacht91
Posts: 10
Joined: Wed May 02, 2012 11:40 am

Re: Down grade with cruise on trans bucks back

Post by Zacht91 »

My truck does this sometimes and its stock. I think its just the cruise trying to slow down to stay at that speed.
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mikel
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Re: Down grade with cruise on trans bucks back

Post by mikel »

Zacht91 wrote:My truck does this sometimes and its stock. I think its just the cruise trying to slow down to stay at that speed.
likely the converter bucking...
Mike Litsch
Holley Technical Sales Manager
Diablo Tech support by phone:
561-908-0040x4
M-F 8:00 AM to 5:00 PM EST
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