Yep. The throttle plate stop screw has ZERO repeat ZERO to do with idle control. If the idle is affected by the stop screw it has been adjusted improperly! In order to get it properly reset you will have to jump through some hoops to put it back the way it should be. NOTE:The following procedure should ONLY be conducted on an engine exhibiting NO VACUUM LEAKS. Any vacuum leak will give a false response and render the adjustment incorrect!

To reset a mis-adjusted throttle plate stop screw you must start and warm the engine to normal operating temperature.

With the truck idling and all accessories OFF, disconnect the IAC. The engine should wind down, sputter and die. If it does not, the throttle plate stop screw is mis-adjusted.

If the adjustment is wrong, shut the engine off and back off the screw until the throttle butterfly plates just fully close in the bores. Note: It can be difficult to get this just right because just after the plates close fully the screw no longer touches the tab on the throttle. (The stop screw ONLY creates a mechanical stop to keep the butterfly plates from sticking in the throttle bores when the throttle is released suddenly and they snap shut).

To determine if you have gotten it right, disconnect the battery for five minutes to clear the fault Codes triggered when you disconnected the IAC. Reconnect battery and IAC. Restart the engine and repeat the disconnect procedure outline above. If the engine winds down sputters and dies, all is correct. Shut it off. Clear Codes again. Reconnect IAC and go for a drive for about 20 minutes so the computer can relearn parameters.

 

Grab a Motorcraft PCV while you're at it if you don't have one, dont bother with the stop screw until you have one. The other brands (tried 3) caused weird idle issues for me.. with the Advance Auto one, I could back my stop screw all the way out without the truck dying. The PCV is suppose to help keep the crankcase vent from receiving full vacuum, the cheapy ones don't do this and makes your engine act like it has a vacuum leak.

I can slap any offbrand PCV valve in and almost guarantee my idle will jump at least 100RPMs when I do it.

Seriously, so many issues chased, money spent, quick fixes and wrong fixes (truck wouldnt run right with my timing set at factory for example). MLPS and Motorcraft PCV valve made the most difference out of all the parts I've replaced. O2 sensor, IAC, MAF sensor, bleh, waste of money.

Thinking about replacing all non-motorcraft parts with motorcraft parts. I don't trust my Autozone TPS or VSS right now either. If you pick up a Motorcraft PCV valve, you'll be surprised at how different it is than the part store valves are, they're completely different in design. If you have an Oreilleys they'll order one, it's about $5 vs. the $2 for offbrands.

 

Time permitting i will look into this cause i know for sure the idle stop screw adjusted the the idle: and when i disconnected the iac(electrical connection)right? it was an unnoticed idle. Back in 2004 , i installed part#f2pz-93f39-a idle engine kit.Its and adapter spacer that sandwinches in between the tb and iac for fine idle adjustments.And also i recall per msd in04 i set the timing (disconnected the spout conn to 12 degree instead of 10 degrees as my sticker under hood called for.TR

 

Error or grey can u still get a motorcraft mlps switch , which did u use? TR

 

Last Motorcraft one I bought from Broadway Ford here in St. Louis. They are a Ford Truck dealer only. (They specialize in fleet service and sales for more of the heavy trucks but supply their fair share of light truck fleets as well).

The design (more accurately the pin configuration) was changed with the E4OD reworking in 94. The old E4OD components are NLA... Ford tossed all the old parts stock once the E4OD was reworked. This is fine though since the new parts are all backward compatible... Did you hear that Microsoft... Bill G.? BACKWARD COMPATIBLE!

At any rate, since the configuration changed, the replacement MLPS for older E4OD's are supplied with detailed instructions for reconfiguring the connector in the wiring harness to be compatible with the redesigned MLPS. It is critical that you take these steps when replacing it or you will damage the MLPS and the transmission.

 

Exactly. The new one is a '95 kit and includes grommets for the older model wire count, configuration and instructions. The connector is on top, not pointing toward the rear. The Ford parts department has to do so some extra computer searching but it was there about six months ago. You just count your wires and use the appropriate grommet. My harness connector worked fine but if you need to change, do it one wire at a time.