Intermittent Miss

[LoosMaster]

I'm registered on this forum and usually hang in the V8 section but I have a Mustang with the 2.3 and it's common on the Ranger. Need some advise on troubleshooting this miss. I have no codes, no lights other than a defective SRS system that's been disabled. This started a few days ago. Happens when engine is cold and after running for about an hour it goes away for the rest of the day until the next morning when engine has time to cool off. It accelerates fine but between 1500 and 2000 there is a miss like a cylinder is cutting out, you can see the tack drop about 200 rpm back and forth. When the engine reaches a no load the miss goes away. If you ever so slightly touch the throttle it starts again until the engine unloads. I've changed the coil, TP and the MAP, the plugs, wires, rotor and cap were changed about a month ago. I've cleaned the throttle body and ran some SeaFoam in the tank. Nothing. I'm going to change the EGR valve next. I have a new TFI but can't figure out what size socket is required to take out the bolts. I have a ***** load of tools and nothing fits. This is on a 1990 Ford Mustang LX with the 2.3L engine, I also have another that's a '92 which is a donor vehicle, except the ignition components. Thanks in advance.

[LoosMaster]

Well I found out today the TFI uses a Torx tip special tool to remove the screws. I replaced the EGR valve yesterday and the miss went away. Not sure if the SeaFoam finely kicked in but there was no miss at all. The old EGR valve was completely jammed shut with carbon. So, hopefully if anything, it will start to get some better gas mileage with all these new parts. I droped another can on SeaFoam in it with a tank fill up just to make sure.

[LoosMaster]

Well, the miss is back. I put on a new TPS, it has better throttle response now but still the kicking at 1500 to 2000 RPM like a miss. Checked the fuel pressure and it's 38lbs with key off, 32lbs engine running. I let it sit for almost an hour and only lost 2 psi on the guage.