Somehow my truck knows when I hit 70 mph in sixth gear. It runs perfectly otherwise but when I hit 70 it's like the fuel is shut off. It picks back up at around 60 and has no codes and no check engine light..anyone have any ideas? I don't want to take it to the shop withoug at least having a clue, why just 70 mph and in sixth? all other gears and rpm ranges are fine..thanks in advance, Larry

edit, I tried unhooking the Edge and it does the same with it plugged in or unplugged

 

I would throw a fuel filter in it before you do anything else.

 

just did it and no change. I had good pressure on my guage before and the filter might have brought it up a little but nothing too noticable, maybe 1/2 lb..why 70 mph only? I cant make the problem show at any other rpm range, only in 6th at 70...never heard of this one and I'm lucky enough to have it

I checked again for any codes...none, all it shows is Pdone--or is that a code. I thought it meant the test was completed

 

Can you go over 70 in 5th gear? If not, what is the limiting speed in 5th gear and does it "die" like it does in 6th gear?

 

I seem to be able to go to redline in 5th which is over 70 but not by much. I have looked at everything I know to look at and this doesn't make any sense to me. I thought it might be the speed sensor on the rear diff but doesnt the tach and spedo drop to zero or fluctuate when the sensor is bad? Im open to try anything..how does it know Im in 6th and trying to go past 70? It'll go past in fifth..wierd huh...drivable but I hate to be limited to below 70..Im open to any and all ideas. I even called my dealer today and they seem to have never heard of anything like this but they said I could make an appointement and bring it in sometime next week...GRRRRRRRRRRRRRRRRRRRR this is only Monday and they cant look at it until next week 'sometime'

 

i was working in a doctors office today and the receptionist was telling someone on the phone that they couldn't get them in until the middle of march, hope it wasn't anything serious.

 

it would be my luck that it's the vp44 but there are no codes so Im hoping maybe it isn't that. I don't know what else to try.

 

You live in Cookie town, plenty of hills, try loading it in fifth up a hill, maybe it is affected by the necessary torque to pull 70. Only other thing I can think of is if the colder air at 70 is affecting IAT or something like that. If it is definately tied to 70 I can only think of the speed sensor. Other than that you are tied to fuel.

 

You running an auto or manual transmission?

 

He's got the six speed manual.

 

Im going to try and clean the IAT tonight and see if it helps..

Haulin, it does it whether towing or not so could it be that sensor on the rear axel? I looked and visually the wire looks ok..