1999, f-350, My problem is when i put the truck in park or nuetral the idle drops to about 600 and it runs rough (shakes the truck). When i put it in drive or reverse it goes to about 700 and runs smooth. Is this normal??? Any sugustions to smooth it out while in park.

 

Of course this is not normal. How many miles do you have, what mods, and how is your maintenance. When was your last fluid change etc. Plenty of folks to help you here, but you gotta help us.

 

Thanks for the reply. 100103 miles, 4 inch exhaust, older 50hp hypertek chip, 4000 miles on rotella oil. large Napa air filter. Regular main. has been done. When i move the shifter either way you can see the tach move. Thanks for the help.