intermittent check engine light & dealer can't find problem

Have 25,000 miles on my GT PP. It is stock except for Ford Racing cat back and MGW shifter.

Starting a few months back the cel will come on for a a few days and then go off for a few days for no apparent reason. The car has always ran great.

Took it to the dealer and they could not find anything wrong, the cel was off at the time I took the car in (back on again now though as of yesterday). I am convinced that the mechanic checked everything he could think of and he seemed like he was a capable individual.

What would you folks do in this situation?

Better yet, anyone had a similar issue and maybe found a solution?

I would run it to an autozone when the light popped on and have them check it for free while it is on. Take a screen shot of the error code (if any) and then take that to ford.

That makes a great deal of sense, didn't know auto zone would do that.

USPSALIMITED said:

That makes a great deal of sense, didn't know auto zone would do that.

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Autozone, Advance, and Oreillys all will pull your codes for free. I suggest you run in when it is on and dont turn off your car that way it stays active if it is a one time code.

Or you could get one of these, I have this one and, for 16 bucks, it is really simple to use to read codes and clear them:

https://www.amazon.com/Autel-MaxiSc...d=1477314966&sr=8-10&keywords=ford+obd+reader

If there is a code in there, it would be set in history. CEL doesn't have to be on. Unfortunately, sometimes, if the car isn't acting up it's impossible to diagnose the issue.

NowhereFast said:

If there is a code in there, it would be set in history. CEL doesn't have to be on. Unfortunately, sometimes, if the car isn't acting up it's impossible to diagnose the issue.

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That is what I thought. The mechanic could not find anything recent, he said there was a code that had popped up when the car had about 80 miles on it.

No worries, I will pursue one of the excellent suggestions above with the cel on.

NowhereFast said:

If there is a code in there, it would be set in history. CEL doesn't have to be on. Unfortunately, sometimes, if the car isn't acting up it's impossible to diagnose the issue.

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This is a huge issue in the industry. Intermittent concerns of any type cost everyone monies. Techs spend time chasing an issue that there is no answer for at that point. Customer gets frustrated.

So I ran by auto zone today while the cel light was on.

Error codes are:
P0300 Random misfire detected
P0308 Cylinder number 8 misfire detected

Their most likely solution is: "Replace crankshaft position sensor (CKP) o-ring.

Part cost would be $29.99, not sure how much labor would be involved. Will run things by my dealer now that there is some info to work with.

This is turning into a saga.
Took car back to dealer today, the cel was on this time, mechanic reported that each cylinder on the right had several indicated misfires on the computer.
Car is still not showing any issues and the mechanic did not know what to do.

Mechanic said that Ford has a fairly new policy regarding technical support. The dealership has to email and wait for a response from Ford instead of calling technical support and getting a prompt response. So they email and I turn around and drive the 40 minutes back home and am pretty much right where I started.

I can understand Ford wanting to save money on technical support services, but this ain't the kind of policy that says we value our customers and please come back when it is time for your next vehicle.

He is somewhat correct. There is no specific tooling we have that tells exactly what the problem is. It is not uncommon for a Ford Tech to submit to our hotline to discuss with an Engineer.

In case anyone cares, the saga with my car continues. The dealer had it for a little over a week and thought they might have found the issue. After about 1 tank worth of driving the problem is back.

Will get it back to the dealer but am getting a bit desperate to get the problem fixed before my warranty expires.

Check the intake manifold. A bunch of guys are having this exact same issue. It's turning out to be cracked manifold runners or IMRC valves broken. There's a thread here if you search around.

any updates on this? Exactly around 25,000 miles and the same issue.

Car is going back to the dealer - am going to forward dev1360's tip "A bunch of guys are having this exact same issue. It's turning out to be cracked manifold runners or IMRC valves broken." .

Otherwise no updates.