when i am driving when i let my foot off the gas it feels like i am pressing on and off the brake, it kind of hops. what could be causing this? it runs really rough especially in first gear.

 

How do the u-joints look? Any play in the driveline? How does it run rough while in 1st?

 

maybe the drive shaft is out of balance.

 

yeah it does run rough in first. drive shaft did run across my mind but im still not sure.

 

Is it running rough like its missing or is the idle fluctuating or what?? Is the motor running rough or is it riding rough?? We need some more details about exactly how its running in order to help.

 

Plug wires?, Hope you fix her, your 85 is one of my fav's here.







"The Marines I have seen around the world have the cleanest bodies, the filthiest minds, the highest morale and the lowest morals of any group of animals I have ever seen. Thank GOD for the United States Marine Corps!" - Eleanore Roosevelt

 

my idle was fluctuating really bad the other day but i replaced my mass air flow sensor and that fixed my idle problem, so now it is only riding rough. its really bad in first gear, and it only does it when its in gear

 

axel wrap?

 

In first gear with a truck that makes 80 rear wheel hp? prob not

 

i understand the drive shaft making the truck run rough, but would it make the idle fluctuate like it does.

 

I think you need to isolate, and be more clear what you mean by "running rough". To me that means an engine performance issue, not some sort of driveline or chassis vibration.

If this is an engine issue, then of course look at things like a general tune up, fuel delivery system, etc.

If it's a vibration when you let off the gas, look at d-shafts, pinion nuts etc.

 

i have a problem almost like 85yota4x4 does but mine runs rough like it is missing at highway speeds and fine at idle

 

Pilot that sounds like plug wires, mine did that. Kind of a skip bump, very subtle, wires fixe that.




"The Marines I have seen around the world have the cleanest bodies, the filthiest minds, the highest morale and the lowest morals of any group of animals I have ever seen. Thank GOD for the United States Marine Corps!" - Eleanore Roosevelt

 

big blues all fixed and running great

 

So....
What was the problem?

 

the cable that goes to the air flow sensor

 

thanks Teuf for the reply, but I changed the wires, the plugs, the cap and rotor,before this started happening, and the fuel filter today to see if that would help it runs fine at idle and as soon as go to drive it, it wont rev very well and when you go to go up a hill it it has no power.I htink it might be the intake, or the crack in the exhust manuifold any other ideas would be alot of help

 

Pilot, your Cat OK?

 

thats what mine did once i unplugged my air flow sensor the idle got good but once i drove it it wouldnt rev good at all