my idle is smoothe and even in park and neutral, but in reverse or drive it is very rough. "bucking" when i give it gas and start moving it goes away. its getting worse. any help?
tim

 

Please state model year and engine size. (Update profile and/or make a signature).

If you have an '81+ then try running the built in self test diagnostics and then read the codes. See info link in my signature.

 

sorry kl ricks i thought i had done that in profile.... 84 f150 351 w edelbrock carb. smog parts removed. will try to follow links for codes. i thought by going back to an 84 carbeurated i had predated computer codes... guess not...

 

now with avatar info and signature! look at me rocketing into technology that is probably 10 years old! now if i can just figure out what i assume is a vaccuum problem..... i have gone through with propane and carb cleaner and cant get the idle to change, but it does fine in park and neutral. i need an assistant so i can try it with it in drive gear which is where it is giving me trouble

 

i suspected the brake booster for the vacuum leak, but without help i couldnt test it in drive gear. ordered a new brake booster.....while waiting i got the idea to coat the grommet and hose fitting on it in silicone. seems to have done the trick. a smart engineer that wasnt trying to sell boosters might make that grommet replaceable.....just saying

 

klricks,
cannot find that connector under the hood. where do thw wires at the other end of the obd connect. i see the grey single one....

 

On my '86 all the wires for both connectors run into the same spot on a wire harness.
If someone has deleted allot of the smog stuff as you say then you might have a hard time sorting out the codes anyway.

It is possible that someone has converted your engine to a pre '80's system...
if so you would have no computer / codes etc.

 

very possible. today my temporary brake boost fix is not doing as good as yesterday. hopefully mr fed ex will have a new one for me today. and hopefully that new one fixes the problem...