Bad driveability and idling

lwrdr2 · 12-26-2007, 05:28 PM

Got a 1996 E-150 with a 5.8. 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. I have no clue. Anybody can help would be appreciated.

Toucan · 12-27-2007, 09:02 PM

Check your air intake system and components. Many time with a spray can of carb cleaner or air intake spray you can solve this problem. Air control... Air filter are worth while looking at

lwrdr2 · 12-30-2007, 09:49 AM

Everything looked good and i did try that. It almost like something is causing it to be held open. I think its kind of ironic that it happened after I got gas.

jonmark1985 · 12-30-2007, 10:52 AM

Yeah, could be bad gas, try changing your fuel filter and getting some fresh gas in the truck.

lwrdr2 · 12-31-2007, 06:07 PM

would that make it idle high though? cuz its only when in gear and driven that it idles high. I mean like when your at a stoplight with foot on brake the engine runs maybe 1200 rmn if you shift into neutral or park it takes aminute and then drops down to a normal 750 rpm or so.

jonmark1985 · 12-31-2007, 08:51 PM

It would make run rough, but I don't imagine it idling fast I'd imagine, thats from a vacuum leak, or a sticking idle air control valve.

lwrdr2 · 01-02-2008, 09:26 PM

I was thinking maybe a bad valve like that or somthing sticking open. It only idles high when its in gear. If it goes in neutral then the RPM drops to a normal level. when you put it back in gear and wait a few seconds the idle speed will jump. Pair that along with the constant black smoke coming out of the tailpipe and i figured it is runnign too rich.

jonmark1985 · 01-03-2008, 07:12 PM

If intake or exhaust valve in question you should do a compression test along all the cylinders.

lwrdr2 · 01-04-2008, 09:06 PM

When i said valve i was thinking of the idle air valve or somethign like that nature not the combustion valves. Hoepfully this weekend it wil be warmer so i can start working on it.

lwrdr2 · 03-23-2008, 07:43 PM

Well its been a couple months and have tried fixign a couple things. Gave it a set of plugs, wires, cap and rotor, and replaced the IAC valve. Still runnign and acting up. Took it to autozone and read the computer and with no CEL on its hard because it states nothings wrong. Same goes for Firestone. Took it in and they hooked it up. Accordign to their computer the same thing. Nothing is wrong. I even joked with the tech nothings wrong as its takign a couple minutes just to even get it started to drive out of the service bay. Anybody else got any other ideas. I took it to my mech who i trust but he isnt sure and said well i can start replacing stuff but thats no guarantee that it will fix the problem. Dont want to strip it out for parts but im getting to that point.