Alright I started out on my family vacation today and we got about 8 hours and several hundred miles knocked out on the first day. Driving up through Mississippi, Alabama and Tennessee so far, who knew it was going to be so hilly. I've driven all the way on the 87 performance tune and was wondering about if the performance I'm getting is normal. I've been using my cruise control as much as possible and when it gets to a point going up a hill where it tries to downshift and gain speed the RPMs fluctuate pretty rapidly up and down. We're not talking big hills either, slight inclines are causing it to do this. I never noticed it ever doing this when the truck was stock and had the stock tune. It's like I'm stomping the gas, letting off, stomping on the gas, letting off. Usuallly I've just been disengaging the cruise and taking over myself.

My tunes are still knew and before today probably had about 30 miles on them. I'm just wondering if this is normal behaviour since the tunes are so new and will this eventually settle out?

 

if you have 3.55 gearing then that would be the problem from what i see

 

Yeah I have the 3.55 gears. So potentially need to regear? I thought as long as I stayed 35" tires and less I wouldn't need to regear. I want an exhaust as my next investment, but may have to rethink that and go with new gears. Any recommendations?

 

Hmm.. I hope this is just a case of the tunes needing more time to acclimate.. I wouldn't think - would hope not - that the tunes written for your 3.55 diff would cause what you describe. I've not read or heard of Troyer's tunes requiring a gear swap just to climb gradual grades.
I'd suspect it's a matter of more miles / cycles on the tune to let everything adjust.. I hope so, I don't want to be told I need to change out my differential in order to navigate the hill country around here!

 

wxscpro....I know exactly what you are describing. When my stock tunes were installed, my cruise control behaved smoothly when trying to pull a slight incline. With one of my custom tunes installed and the cruise set, the truck, when pulling a slight incline, will accelerate up and down, kind of a pulsating type of rhythm back a forth. My truck has the stock tires and 3:73 gears, so it has to be the tuning program causing this.

 

On the contrary, my vehicle performs much better on cruise than it did in the stock form. The trip form my home to Mikes shop includes the West Virginia Turnpike which has some very long steep grades. I have minimal downshift on the climbs and the speed holds where it is set on the 7% downgrades which some are several miles long.

 

My truck was experiencing the same thing. With cruise control reving up and down (pulsating) before it would shift. Mike did send me another tune to try, but I switched intakes before I can try it. I contact Mike and soon as I can get some time off, I'll be heading down to get it on the dyno. Give Mike an let him know what's going on.

 

There are so many variables like how much weight do you have loaded in the truck.70 mph is where the OD locks in and out in my truck when I am pullen a trailer,kinda feels like a passing gear kicking in and out.I adjust the cruise to correct the problem,and make mental expectations based on the circumstances and plan accordingly.There are many threads about towing and the OD. gear.As for the 3:55 nothing wrong with them unless you plan on 1/4 mile drags, or full block burnouts.

 

I would think you would probley want to put your truck into 87 two when doing stuff like then. I remember when I red the info that mike sent me it said. DO NOT TOW IN THE DRAG RACE TUNE. I think the shifts and power are more set up for dragraing then towing. And with your truck lifted the motor and tranny working harder and with the high gear ratio you have. Your truck basicly is towing all the time.

 

Mine works much better after the tune with the cruise on. Before it was hunting for gears and now it holds the gear it starts in.

 

Ok just now able to get back to an internet connection, still on vacation. You describe exactly what I am experiencing. I may have to call and talk to Mike when I get back. It's not everytime that it'll do this, but it does it more times than not. Sometimes it'll hold the speed pretty good and I think that's what it's supposed to be doing. Glad to hear though it's not just me experiencing this issue and it's not a gear related thing.

 

My trip from home to Mikes shop along the West Virginia Turnpike experienced little downshifting on the climbs and the speed held where I had it set which may have been near 80.

 

Alright made the drive from Ohio to Missouri yesterday and am still experiencing this issue. Tunes have over 2000 miles on them so the break in period should be over by now. I am noticing that the issue arises mainly when I have my cruise set around 70mph so not sure if it has something to do with a certain speed setting or not. Maybe I will experiment a little more with differing speeds when I make the final leg and head back to MS next week. Other than this issue the tunes are performing great and giving me all the power I need to get around cars and get up and down the hills with absolutely no problem.