Truck had been running fine until a big oil leak from the oil pan gasket developed. $600 later with a new gasket (valve cover gaskets were replaced too) the truck ran like a champ. Now no longer. Starts up fine and idles at about 700RPM. Put in gear and it drops to 500 but quickly levels back to 700. Drives fine with good acceleration, but if I put it in park or neutral it stalls right out. Restarting it and it runs fine again. Back in park and it stalls out. Stepping on the gas raises it but it will stall out if I let off. What could it be??
I replaced the Air bypass valve and all the filters and cleaned the throttle body.
HELP!!

 

Have you checked for any stored fault codes ? There are a few possibilities as to what may be causing the problem so check for any codes & post back .

 

Don't have a code reader. Could it be the EGR or TPS? I have been looking at the posts here and some of them refer to that. Seems weird that putting it in park or neutral makes it die out, and if I restart it it idles fine. It's the load shift from the tranny that seems to be doing it. Putting on the AC dosen't affect it.

 

Could your O2 Sensor have oil in the plug? I remember reading about oil and fluid leaks getting in the connection of them. HTH

Brian

NOTE: My O2 sensor is in the exhaust pipe just under the manifold on the passenger side.

 

That is very weird, that it stalls out when REMOVING the load! It would seem at idle, no load, that the IAC would be down near minimum airflow, the injectors would be at minimum pulse width, etc. with no load. I really can't think of much. When it dies, is it just like it idled down too low to keep going, or does it idle rich and rough with some black smoke and then die?

 

I will detail exactly what it is doing:
Start up truck cold, idles at 1500 for about 20 secs then drops down slowly. after about a minute will level off at 600-700 rpm. It is a fairly steady idle with no miss or shudder.
Pop it into drive and the idle drops to 500 then ups to 700 again and stays steady.
I can drive it around the block a few times, and as I stop at a light it's idle is steady at 600-700 rpm. At that point I put it into neutral and the idle drops quickly to 500, 400, then just drops to 0 and stalls. I then turn the key to start it again and it starts right up and idles at 600-700 RPM. Wait a few minutes then try the car in drive. Drops to 500 then jumps back to 600-700 and steady. Put it in neutral again and it drops down fairly quickly and dies. The last thing done to the truck was have a service station repair a oil pan leak whick needed the engine lifted to do it. They did crack a exhaust pipe which caused a rough idle but they fixed that and the truck ran great for about a week. Now I have this dying problem.

 

Let's not forget the simple stuff first. Try disconecting the battery for 5 min. or so to re-set the computer. If it still has trouble, get your codes read and go from there.

 

That last trick worked! I disconected the battery for 15 mins, then put it back on. Now the truck works great!!