Engine Performance problem
1996 Ford E-Series Van V8 Two Wheel Drive Automatic 152500 miles
Ok heres the deal. My 1996 E-150 conversion with a 5.8L engine. Normally pretty reliable but now a wierd problem started and im having trouble figuring out whatswrong. ITs got 152K on it. The other day it was driving fine all day. I had about a 1/4 tank or gas in it. Stopped at the gas station and put $20 in it. Diving later the idle started runnign high and then it stalled out. Now it does still start but when driving it if you give it gas of floor it black smoke comes out of the tail pipe. When driving it and you are at a stoplight with foot on the brake the idle seems to be running about maybe 1500 rpm or so. (Im guessing since there is no tach) if you shift back into neutral then the idle will go down. If you shift back into drive or reverse they after a couple seconds the idle will jump back up again. IT will idle high enough so that it can accelerate on its own and top out around 30-35 mph. THere are no check engine lights on so according to the computer there are no problems. Im thinking maybe a clogged cat convertor? Bad idle air valve? Since there are no check eng lights on I cant say whats wrong. I have no clue. Anybody can help would be appreciated.