[LOWbutnotSLOW]

Hey everybody. I got a bagged Ranger with a 5.0L and I am having a low idle issue as well as a vacuum question. I was having an issue with the idle and a lean misfire off idle so I did my spring tune up of plugs, wires, cap, rotor, and carb tune. The RPM idle is 800. The lean misfire off idle is gone, but the truck still spudders while cruising in 2nd at 2500-3000RPM. The other thing is with the brake booster line disconnected and UNBLOCKED the pedal gets better (usually spongy and low) and the RPM gets to around 950 with no spuddering. What could be going on?

PS I bled the brakes and there are no leaks in the brakes anywhere.

Thanks for any help.

[fast68]

not enough fuel or too much air(vacuum leak somewhere)

weak FP?

intake gasket failed?

carb base gasket failed or is wrong one for the carb or intake?

ive had the last thing wrong on a late 70s 351 truck we had,

a different and correct base gasket fixed it

was horrible idling and low rpm running was not right.

ford used several different ones depending on year make model on same engines even

a pita........