Being held back? Performance issue
Thread Starter
Junior Member
Joined: Nov 2010
Posts: 26
Likes: 2
From: Twin Cities Metro Area
Being held back? Performance issue
Hey Gang,
Got a question about the ol' girl I've been working on.
Since my last post (Sometime last year I think) my 91 F150 got some new repairs including a new ECM, Rebuilt Transmission and new Radiator.
Surprisingly enough, she still bucks and labors to shift when I have to apply faster acceleration or going up hills (using the same amount of acceleration). City/slow speed driving is now fine.
I've developed a 'feel' for the old beast and to me it feels like she's being held back somehow, like it's more work then it has to be just to "go" which is why I think the trans is still labor-shifting and it doesn't need to be.
So here's my question:
Any thoughts on what else this whole shift-buck issue could be? On my end, I've shifted my focus to a couple of things:
1. Electrical system (Trans guy said it had some when he worked on the rebuild)
2. Drivetrain (The frame and axels are rustier then the Titanic [or so it appears]. Any ideas on how to grease/oil/lube things to smooth out operation? I've already lubed the Chassis in 7 areas)
3. Accelerator (Seems much harder to compress then every other vehicle I've driven recently. Not sure this is normal)
Any help or thoughts are greatly appreciated!
Thanks much,
91HT
Got a question about the ol' girl I've been working on.
Since my last post (Sometime last year I think) my 91 F150 got some new repairs including a new ECM, Rebuilt Transmission and new Radiator.
Surprisingly enough, she still bucks and labors to shift when I have to apply faster acceleration or going up hills (using the same amount of acceleration). City/slow speed driving is now fine.
I've developed a 'feel' for the old beast and to me it feels like she's being held back somehow, like it's more work then it has to be just to "go" which is why I think the trans is still labor-shifting and it doesn't need to be.
So here's my question:
Any thoughts on what else this whole shift-buck issue could be? On my end, I've shifted my focus to a couple of things:
1. Electrical system (Trans guy said it had some when he worked on the rebuild)
2. Drivetrain (The frame and axels are rustier then the Titanic [or so it appears]. Any ideas on how to grease/oil/lube things to smooth out operation? I've already lubed the Chassis in 7 areas)
3. Accelerator (Seems much harder to compress then every other vehicle I've driven recently. Not sure this is normal)
Any help or thoughts are greatly appreciated!
Thanks much,
91HT
Thread Starter
Junior Member
Joined: Nov 2010
Posts: 26
Likes: 2
From: Twin Cities Metro Area
-Update-
While out driving yesterday, I couldn't help but notice shifting at greater acceleration taking place between 2500-3000 rpms (Feels like engine and Transmission are out of sync at higher RPMS). This doesn't seem right so, at the recommendation of a much more mechanically inclined friend, I'm running Seafoam through both the intake and the fuel system.
Never used it before and I doubt the truck has had this done either. Here's hoping the seafoam helps at least get back some performance.
I'll update again when I find out more.
-91HT
Never used it before and I doubt the truck has had this done either. Here's hoping the seafoam helps at least get back some performance.
I'll update again when I find out more.
-91HT
Jordan
Joined: Jan 2011
Posts: 7,867
Likes: 30
From: Chico, California
First things I would eliminate would be the Throttle position sensor, and the Vss. Like maybe the transmission isn't getting a good signal from the pcm for when to do what. Im pretty sure the VSS also gives information to the transmission... Could be wrong though.