malo012000

My 5.0 when it starts and after it comes down off a hi idle to a normal idle it surges and then stalls but if I start driving it down the street buy the time I get to the first stop sign It will run fine also when I slow down and roll in gear it surges also ...Like taking a turn in second and not giving gas but not going slow enough to stall it ,it surges until I get on the gas ...Please HELP I have since check for vacuum and could not find any so can any one help me

JPJP

My '86 used to do something very similar but not as pronounced as yours. I wound up changing many things (Throttle pos. sensor, Idle Air control valve cleaning, aftermarket chip, Intake air temp. sensor....just to name a few things) and couldn't pin point the issue. I supercharged it with an older SN Paxton venting the PCV valve to the atmosphere and it got better.

I also put a screw on breather on the valve cover (at oil filler) and removed the line from the valve cover to the throttle body and plugged the ports. The breather made a huge difference. It isn't perfect but much much more managable.
Also, check to make sure you don't have a bad vacuum leak somewhere.

86 5.0L

most likely a vacuum leak

JPJP

Check the back side of the lower intake manifold for vacuum leak/blown gasket. Hard to find but was a source of a huge oil leak I had on mine which I fixed once I supercharged it. Could have been a cause of vacuum leak as mentioned by above poster.