I have :

1994 Ford Explorer V6
110,000 miles on it.
New: Coil Pack, 8mm Plug wires, Bosch Platinum Plugs, MAF was cleaned, new IABV, transmission fluid and filter, oil and filter, air filter, etc. etc. etc.
2.25" True Dual Exhaust - Dual in/out HiFlow Cat, Dual in/out Flowmaster 40
19lb Inj (stock)
K&N Cold Air Intake
66mm Throttle Body
55mm Mass Air Flow Sensor
3000cfm E-fan set at 180 (removed clutch fan)
I drive it like I stole it.

Start it up and she idles at about 950rpms.
Idle sounds very clean at this point.
Now put it in drive and idle drops to about 560ish but still sounds very clean.
Now, take it out on the street and tach. above 3000rpm, come the a stop but keep it in drive and the idle kind of lopes and backfires enough to make the truck shake.
Put it in Park the idle jumps back up to 950rpm, the shake is gone but now you can still hear it in the idle.
No other problems at all, drives fine in the city on the highway.
WOT response is good.
Cold, warm or hot day it acts the same.
Cheap gas, Good gas, all the same.
Ran three tanks of SeaFoam Inj. cleaner, no change.


At first I thought the torque converter might be trying to lock up on me, but the more I think about it, it sounds like I have an injector that’s leaking fuel and then when the hollow spark hits it, fighting the exhaust stroke of one of the cylinders, making it shake in a lope/backfire.

Right?

Or am I over looking something. The only other things I think it could be are the EDIS6 or the EEC-IV.

Thank you for your time.