1993 LX 5.0 dies after ignition parts replacement

Warhorse85 · Aug 16, 2025

Hello everyone, I'm having trouble figuring out why my wifes 1993 LX 5.0 dies while idling after replacing some ignition parts. The parts I have replaced are the MAF, TFI module and ignition coil. EGR was replaced last year. Car starts and runs great but after idling for a bit it surges for a couple of seconds then goes back to idling normal then about 5-10 seconds later it just dies as if someone turned the ignition key off. It will instantly restart and idle with no issue for a few minutes and do the exact same thing. I did notice that there is a loud buzzing noise coming from the EGR area while it's idling. Any help would be greatly appreciated.

AeroCoupe · Aug 17, 2025

Basic things that you need to provide in a thread like this.
Stick or Auto?
Mods
Any codes?
What were the name brand of the parts that you used to replace the existing parts and why did you replace them?

The check engine light (CEL) only illuminates for emissions related codes. There can be codes and no CEL so if you have not scanned for codes please do so.

Warhorse85 · Aug 17, 2025

AeroCoupe said:
Basic things that you need to provide in a thread like this.
Stick or Auto?
Mods
Any codes?
What were the name brand of the parts that you used to replace the existing parts and why did you replace them?

The check engine light (CEL) only illuminates for emissions related codes. There can be codes and no CEL so if you have not scanned for codes please do so.

All parts replaced were Motorcraft. Car is an automatic convertible. The specific parts were replaced because my wife was driving home from work on the expressway and the engine was surging, then backfired, then ran and shut off as if the ignition key was turned off and no restart. Got it towed home and found no spark and no ground pulse to the coil. No codes other than the ones relating to me removing the smog pump years ago and no check engine light

AeroCoupe · Aug 17, 2025

Man that helps a lot! I would think there would have been several codes with what you described.

My guess would be the ECU needs to be gone through. We are seeing a lot of this as these are now 30+ years old and several of the components are timing out. We are having great luck with The ECU Exchange.

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Only other thing I can think it would be is the PIP but with the ECU not giving codes for the scenario you described that would just be throwing more parts at it.

Warhorse85 · Aug 17, 2025

AeroCoupe said:
Man that helps a lot! I would think there would have been several codes with what you described.

My guess would be the ECU needs to be gone through. We are seeing a lot of this as these are now 30+ years old and several of the components are timing out. We are having great luck with The ECU Exchange.

Ford Mustang 5.0 A9L A9P C3W A3M X3Z ECU Repair Service

Ford Mustang 5.0 A9L A9P C3W A3M X3Z ECUEngine Computer Repair ServicePlease fill out the R&R form here once you've placed your order.A Trusted Product with LIFETIME WARRANTY QUICK TURN AROUND TIMEDomestic and International Shipping available! Our Team is Available Monday - Friday 9am to 5pm...

www.theecuexchange.com

Only other thing I can think it would be is the PIP but with the ECU not giving codes for the scenario you described that would just be throwing more parts at it.

I had a thought though. The EGR was making a loud buzzing noise while it was running. I was leaning towards a defensive EGR and/or IAC. When I got the car running after replacing the parts, I backed down to the end of my driveway, put in drive and slammed the throttle and it spun the tires, which it's never done before. I also did a power brake and not only did it screech the rear tires, it overpowered the brakes and pushed the car forward

AeroCoupe · Aug 17, 2025

Did you remove the old thermal pasted and put new thermal paste between the distributor and the TFI? We usually recommend this one:

Amazon.com

Also, I’ve asked one of the mods to combine both your threads into one. This helps keep all the info in one thread which greatly helps trouble shoot.

I will say that having the ECU gone through is money well spent.

Warhorse85 · Aug 17, 2025

I actually just learned about the thermal paste, and no I did not put any on the TFI. I will go get some and redo it. The car starts and idles beautifully until it gets hot and then it just shuts off as if the ignition key was turned off. It will immediately restart with no hiccups at all

AeroCoupe · Aug 17, 2025

TFI may be overheating. It uses the aluminum distributor as a heat sink and if it cannot transfer the heat it will quit working.

Be sure to clean all the old stuff off. Brake cleaner on a rag does the trick. Carb cleaner will leave a residue so stick with the brake cleaner.

Warhorse85 · Aug 17, 2025

Ok!! Thank you. I will redo the tfi and add thermal paste. Give me a day or two and I will reply with results

nickyb · Aug 17, 2025

I've had trouble with replacement tfi modules, if the paste doesn't help try the old module ,if you still have it.
I found the paste at a computer store.

Warhorse85 · Aug 17, 2025

I would hope not with mine. It's a genuine motorcraft part

gkomo · Aug 17, 2025

I think what he’s alluding to is even the Motorcraft ones can not be good out of the box. Seems things aren’t built like they used to be.

I have a spare Motorcraft one (new) sitting in a box. No need to replace mine but I bought one just in case.

nickyb · Aug 17, 2025

Motor craft is now Chinese made

KRUISR · Aug 17, 2025

I would bet they were subcontracted out to third parties even when the cars were brand new. The automakers don't make the parts in their own cars much anymore.

AeroCoupe · Aug 17, 2025

At that time my guess would have been Mexico or Canada with some of the electronics from Taiwan and the like.

KRUISR · Aug 17, 2025

What I meant was the parts were made by Standard Motor Products, Magna, Linamar, etc., not at a Ford owned plant. Sure, now all those companies manufacture overseas - hence made in China.

General karthief · Aug 18, 2025

Take a gander at the ignition switch under the dash, not the key cylinder, they tend to loosen up and overheat the plug/connector, same symptoms as the overheating TFI.

Warhorse85 · Aug 20, 2025

AeroCoupe said:
Man that helps a lot! I would think there would have been several codes with what you described.

My guess would be the ECU needs to be gone through. We are seeing a lot of this as these are now 30+ years old and several of the components are timing out. We are having great luck with The ECU Exchange.

Ford Mustang 5.0 A9L A9P C3W A3M X3Z ECU Repair Service

Ford Mustang 5.0 A9L A9P C3W A3M X3Z ECUEngine Computer Repair ServicePlease fill out the R&R form here once you've placed your order.A Trusted Product with LIFETIME WARRANTY QUICK TURN AROUND TIMEDomestic and International Shipping available! Our Team is Available Monday - Friday 9am to 5pm...

www.theecuexchange.com

Only other thing I can think it would be is the PIP but with the ECU not giving codes for the scenario you described that would just be throwing more parts at it.

So I added thermal paste to the new TFI and no start. I reinstalled the old TFI and it struggled to stay running and then died. I disconnected the SPOUT connector and it started and then I set the timing and it ran for about 5-10 then died as if the ignition key was turned off and no restart. With the SPOUT connector disconnected I have spark and ground pulse at the 2 wire coil plug while cranking. Fuel pump does come on and primes when key is turned on.

Warhorse85 · Aug 20, 2025

General karthief said:
Take a gander at the ignition switch under the dash, not the key cylinder, they tend to loosen up and overheat the plug/connector, same symptoms as the overheating TFI.

That is is going to be my next part to look at. I actually replaced it 3 years ago when I bout the car because it was bad

AeroCoupe · Aug 20, 2025

So I would be looking ant either the PIP in the distributor or the ECU unless you find a wiring problem.

If you can pull codes and see if anything new has come up.

1993 LX 5.0 dies after ignition parts replacement

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lube between the nut and the face. I know my lubes

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lube between the nut and the face. I know my lubes

Member

lube between the nut and the face. I know my lubes

Member

lube between the nut and the face. I know my lubes

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I gotta say i never painted my nuts, Never Ever

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now i can hopefully expect to receive the shaft

I gotta say i never painted my nuts, Never Ever

lube between the nut and the face. I know my lubes

wonder how much it would cost to ship you a pair

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Member

lube between the nut and the face. I know my lubes

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