New member with idle issues

[old55pete]

Yes thanks for the info. I didnt realize I was replying to a thread when I saw the email response.

There was a recall on the IAC valve that pretty much the same symptoms as what you are talking about. To find out for sure if that recall has been done, there should be an emishion recall sticker on the header panel in front of the radiator.

Another thing I found out was that the grounds needed to be cleaned up. There is a ground connection in the stock ground cable between the batterie and the engine block. It attaches to the frame by the right engine mount. If it is not hooked up, it will cause something similar. There is also a ground cable that goes from a stud on the firewall by the wiper motor to a stud on the lower, left side, by the inside rear corner of the valve cover. The stud is one of the lower intake manifold mounting bolts. If ether end is dirty, it will cause similar problems.

In your shotgun list of parts replacement, I dident see that the TFI module had been changed. Has the TFI module been changed in the last few years? They have a bad habit of failing with similar symptoms also. The strange thing about the TFI is that it will over heat and fail and once it cools off it will work again

[grumpin]

There was a recall on the IAC valve that pretty much the same symptoms as what you are talking about. To find out for sure if that recall has been done, there should be an emishion recall sticker on the header panel in front of the radiator.

Another thing I found out was that the grounds needed to be cleaned up. There is a ground connection in the stock ground cable between the batterie and the engine block. It attaches to the frame by the right engine mount. If it is not hooked up, it will cause something similar. There is also a ground cable that goes from a stud on the firewall by the wiper motor to a stud on the lower, left side, by the inside rear corner of the valve cover. The stud is one of the lower intake manifold mounting bolts. If ether end is dirty, it will cause similar problems.

In your shotgun list of parts replacement, I dident see that the TFI module had been changed. Has the TFI module been changed in the last few years? They have a bad habit of failing with similar symptoms also. The strange thing about the TFI is that it will over heat and fail and once it cools off it will work again

Welcome!

[ArdWrknTrk]

There was a recall on the IAC valve that pretty much the same symptoms as what you are talking about. To find out for sure if that recall has been done, there should be an emishion recall sticker on the header panel in front of the radiator.

Another thing I found out was that the grounds needed to be cleaned up. There is a ground connection in the stock ground cable between the batterie and the engine block. It attaches to the frame by the right engine mount. If it is not hooked up, it will cause something similar. There is also a ground cable that goes from a stud on the firewall by the wiper motor to a stud on the lower, left side, by the inside rear corner of the valve cover. The stud is one of the lower intake manifold mounting bolts. If ether end is dirty, it will cause similar problems.

In your shotgun list of parts replacement, I dident see that the TFI module had been changed. Has the TFI module been changed in the last few years? They have a bad habit of failing with similar symptoms also. The strange thing about the TFI is that it will over heat and fail and once it cools off it will work again

It really does sound like an IAC.. or the TPS.

Micah, did you ohm those components once you installed them?

[MBC1980]

It really does sound like an IAC.. or the TPS.

Micah, did you ohm those components once you installed them?

No but I can check that out. What reading should I get?

[ArdWrknTrk]

No but I can check that out. What reading should I get?

I forgot exactly where the TPS voltage should be.

It's value is probably in the EVTM troubleshooting section.

Bill Vose is a wiz with these things. (He should be, having run a tune-up shop for years)

Two things I keep forgetting about the 5.0 is that the IAC has a diode to help isolate it and that they have a knock sensor.

If you have a timing light you might try seeing what is happening when the truck struggles or dies when cold.

You might also try locking the timing to see if the truck has a steady idle and keeps running without the ECM meddling.

Have you measured the fuel pressure or checked for contamination in the vacuum line after the regulator?

[old55pete]

I forgot exactly where the TPS voltage should be.

It's value is probably in the EVTM troubleshooting section.

Bill Vose is a wiz with these things. (He should be, having run a tune-up shop for years)

Two things I keep forgetting about the 5.0 is that the IAC has a diode to help isolate it and that they have a knock sensor.

If you have a timing light you might try seeing what is happening when the truck struggles or dies when cold.

You might also try locking the timing to see if the truck has a steady idle and keeps running without the ECM meddling.

Have you measured the fuel pressure or checked for contamination in the vacuum line after the regulator?

With the ignition on, engine not running. The voltage at the TPS needs to be 1 volt. Keep in mind that the TPS has NO adjustment.

[MBC1980]

I forgot exactly where the TPS voltage should be.

It's value is probably in the EVTM troubleshooting section.

Bill Vose is a wiz with these things. (He should be, having run a tune-up shop for years)

Two things I keep forgetting about the 5.0 is that the IAC has a diode to help isolate it and that they have a knock sensor.

If you have a timing light you might try seeing what is happening when the truck struggles or dies when cold.

You might also try locking the timing to see if the truck has a steady idle and keeps running without the ECM meddling.

Have you measured the fuel pressure or checked for contamination in the vacuum line after the regulator?

I didnt check the line after the regulator but will do that and will check the grounds to the engine. Fuel pressure is good.

[ArdWrknTrk]

I didnt check the line after the regulator but will do that and will check the grounds to the engine. Fuel pressure is good.

If the regulator is holding 40 you should be good.

I just go through all these quick checks in my mind as I think of how to quickly eliminate possibilities.

[MBC1980]

Welcome to the forum Micah! http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/waving_orig.gif

Gorgeous truck.

One thing that was common, caused stalling especially off the line, was failure of the Thick Film Ignition system.

So much that Ford was forced to replace them in tens of millions of vehicles after a few deaths and class action suits.

The factory placed the module on the distributor, using it as a heatsink.

What's usually done to remedy that is to relocate it to the drivers side inner fender with a dedicated heatsink.

FatFoxx and McCauley Racing both have kits available.

This MAY be your issue.

Accurate diagnosis is the first step.

I replaced the tfi module today and also the coolant temp sensor. The sensor was corroded and broke on half. Also had a bad wire on the coil. All fixed but no luck on fixing the skip and surging.

[MBC1980]

There was a recall on the IAC valve that pretty much the same symptoms as what you are talking about. To find out for sure if that recall has been done, there should be an emishion recall sticker on the header panel in front of the radiator.

Another thing I found out was that the grounds needed to be cleaned up. There is a ground connection in the stock ground cable between the batterie and the engine block. It attaches to the frame by the right engine mount. If it is not hooked up, it will cause something similar. There is also a ground cable that goes from a stud on the firewall by the wiper motor to a stud on the lower, left side, by the inside rear corner of the valve cover. The stud is one of the lower intake manifold mounting bolts. If ether end is dirty, it will cause similar problems.

In your shotgun list of parts replacement, I dident see that the TFI module had been changed. Has the TFI module been changed in the last few years? They have a bad habit of failing with similar symptoms also. The strange thing about the TFI is that it will over heat and fail and once it cools off it will work again

My grounds were on tight but are corroded. Would this affect idle and surging?