Idle surging?

[turboburb]

Before I describe this I will say that I have already used the search button and I have checked out all the usual inexpensive suspects. Electrical system is fine, fuel filter and fuel pump are new. Truck has 172k with a stock inj pump and stock pmd/fsd. Tranny has been ruled out with a fluid flush, filter change and converter inspection.
All starts are fine hot or cold, but on hot starts at idle the truck feels like it has a lopey cam with the occasional surge to 1000 rpms and rare stall. Started out only in a drive gear, but has evolved to P,N,and drive gears. At traffic lights if I am not covering the brake good it will lunge me into the car in front of me. It is an intermittent problem that mostly happens after full temp is reached and a hot start. 3 or 4 point u-turns are out of the question due to stalling at idle rpms, switching from R to D. This does not seem to follow the symptoms for inj pump or pmd but I have not ruled it out. I have no problems whatsoever once I am rolling. Any ideas! I am fixing to drive this thing off of the nearest cliff!!!!!

[turboburb]

One more thing! No DTC's and paramaters looked good as far as I could tell through Autotap.

[charliepeterson]

I'd guess that the Injection Pump is causing the issues. At 172K. it doesn't owe anyone any money.

These pumps can fail with no codes logged, though definitely not as common as electronic failures.

The next time it starts to run away at the stop light, pull over somewhere and in park slowly bring the RPM's up to about 1100. I bet it takes off to over red line with no more accelerator movement. It will come back down when you take your foot out of the throttle.

[turboburb]

Thanks for the advice, unfortunatley I two foot it at most lights and hold the idle around 1000 to prevent the surging and stalls and I have no run away throttle problems. I have read over 50 threads dating back to 2003 and it seems to me that there is not a difinitive symptom of the IP or the FSD going out. Every truck seems to react differently. Mine does not stall at cruising speeds and does not have hot start problems. It occurs mainly after shifting into a drive gear from park or at idle after a minute or so. Murphy's law states that if replace the IP the FSD will be the problem and if I replace the FSD the IP will be problem. Like I said where's the nearest cliff???????????
Sam

[charliepeterson]

If you pull the Intake off you have very good access to the harness feeding the Injection Pump. Maybe it's laying on an Injector line and rubbing somewhere?

[JohnC]

I'd check the lift pump and change the fuel filter first. At idle, low fuel rates, changes in the inlet fuel pressure are magnified.