Truck is a 89 f250 351 zf tranny. We were having issues with the truck wanting to die when releasing the clutch so we took it and had a new slave cylinder and clutch kit installed. This helped the drive-ability some but its still not right. When letting out the clutch I have to be overly light with it and feather it or the truck wants to die. I also feel like the rpms have to be higher than usual to take off also. The other thing is at stoplight the truck rocks back and forth. It has a cam but I drove it for a year and it never rocked like this. So what do you guys think it is? IAC? Timing?
Thanks

 

Anyone? I think this should be something simple I just don't know where to start.

 

one more time...

 

Have you checked for codes in the computer? It might not tell you exactly what's wrong, but may give a general direction of where to start looking.

 

i had some what of the same problem with my automatic truck it was the timing just a good idea to check that, that can mess up your whole driveablity. Or check for leaks around the intake/vaccum area one open vaccum port can be alittle problem that can throw the whole motor off.

 

I would also start by checking for vacuum leaks. How much vacuum does it pull at idle?

 

I'm pretty sure it's a sensor, try the IAC or TPS, but before anything else, check for codes, that's usually the faster way to point at the cause.