crown vic intermittent shut down

ttocs · Mar 9, 2026

the ignition is doubtful but possible. Keep the ignition with you as well as a small pick tool and if/when it does it again you can pop it out and try the new one. If it does not help I would put the old one back and keep it for a spare but it is worth a try if you already have the part. They are easy to swap out.

SnakeBit! · Mar 9, 2026

Thanks!!! The problem is, it cannot be duplicated and when it does it, it usually won't start, (it will crank) until the second time I crank it and then it's fine for who knows how long....couple of weeks, couple of months, I never know. and it has no pattern of any kind, speed doesn't matter, accelerating or decelerating, turns, slowing, braking, fuel level, nothing is the same each time. and it cranks and starts within seconds of when it does it. Crazy.

ttocs · Mar 9, 2026

ok so on the 2nd turn of the key it will turn over? If it were me I would wonder about the fuel then. Turning it a 2nd time primes the line a 2nd time and might increase the pressure enough to get it to start. Has it been started a little slower by chance? It could be as simple as running some injector cleaner through it, it could need a new fuel pump...

SnakeBit! · Mar 9, 2026

a few times in the past, it didn't start on the first try and needed a second crank. I can hear the pump every time I turn the key but very briefly. but most times it does start on the first try. I put an Aeromotive 1000 fuel pump in it about maybe 4 years ago in prep for a Vortech, but then changed my mind about boost.

RAU03MACH · Mar 9, 2026

i used to have an 88 f150 that would shut down in the middle of the road just die
it was an intermittent thing
one day I was messing with fuel relays and fond the culprit
the wire terminal was barely hanging on the post of the relay, but it was not connected to the relay
it was kind of wedged against the post any vibration on the fuse relay box down she goes
fixed that no more problems
just check the entire fuse box just adding

RAU03MACH · Mar 9, 2026

This would also go for anything that is electrical ecu , fuel drive, spark .ect

SnakeBit! · Mar 10, 2026

RAU03MACH said:
i used to have an 88 f150 that would shut down in the middle of the road just die
it was an intermittent thing
one day I was messing with fuel relays and fond the culprit
the wire terminal was barely hanging on the post of the relay, but it was not connected to the relay
it was kind of wedged against the post any vibration on the fuse relay box down she goes
fixed that no more problems
just check the entire fuse box just adding

Thanks!!!! I may replace it just for grins too. not that much.
I would think that a relay would throw a CEL. so far, no CEL whenever it has happened and a check with a "standard" scan tool reveals no codes. a deep history scan with a professional scan tool revealed stored P2105, forced engine shutdown. on fords that only sets the wrench light which it did only once of the many times it shut down. that was what prompted the deep scan and the replacement of the TB and associated electronics.

ttocs · Mar 10, 2026

it depends on which contact to the relay was losing connection. If it were to the trigger wire or the ground on the other side it might throw a CEL but if it was just the input/output of the relay it might not notice or just the opposite. There are two sides of a relay and I don't think our cars are modern enough to check both sides.

SnakeBit! · Mar 11, 2026

Interesting. thanks for that information.

RAU03MACH · Mar 12, 2026

That's the down side sometimes the test equipment won't pick up the fault code or there won't be a fault code
That what was going on with mine no check engine light
Another test you can try
Let the vehicle run in park start shaking wire harness
And connectors
Listening for any changes
Good luck

Todd in KS · Mar 12, 2026

My son is a heavy equipment mechanic and one of the brands has a "Shake" mode. You can have it watch at a particular circuit and then walk around and shake the wire bundles. It will pick up intermittent discontinuities. Pretty cool.

ttocs · Mar 12, 2026

true story - I was in my first freshman year at college/tech school and we were building a circuit that the instructor had just explained to us so we can test and verify everything to learn. From the row behind me my friend Chad told the instructor that his signal generator did not seem to be working(we were doing ac circuits). The instructor weighed over 300 lbs and had it set up so he could write on the overhead projector that was shown on the board so that he never had to get up because of his size. Mr birch started to ask about the settings he had everything turned to on the generator to confirm it was on, set to sign wave and correct freq and finally after everything sounded ok he started to get up. Needless to say at his size he did not move quickly and in the 10 secs it took him to get to his feet behind me I heard two "WHACK WHACK" that could be easily recognized as Chad smacking around the university equipment. Just about the time I was expecting to hear the instructor tell him not to do that, Chad suddenly announced he had fixed it! Now that mr birch had struggled to his feet he decided to make the most of the situation and I shit you not actually told the one student that always slept to wake up because this was important. He then went on to tell us that he didn't hit it, he didn't smack it, and he did not beat on it what he did was called technical taps. We thought he was kidding till he told us that the term goes all the way back to the old vac tubes prior to transistors because the holder they snapped into would develop some corrosion over time as well as expand till it was not making enough of a contact to work. They could fix them by simply tapping their fingers on top of the tubes and you would be amazed how much stuff is diagnosed like this. I saw it done to million dollar semiconductor manf machines as well as on high end cars. Mr birch told us that we could diagnose a LOT of problems like this, and we can bill for it as well..... One of the best lessons I learned in tech school honestly.

RAU03MACH · Mar 12, 2026

My ford star tester has the wiggle play test on it
Most of the dealerships have that test feature

SnakeBit! · Mar 12, 2026

I did the wiggle test a couple oi times to no avail. If it does it again, I will try it again.
I'm going to replace the fuel relay in any case. I am also going to get one of the circuit testers that allows you to run the probe along the wires to determine any breaks.

SnakeBit! · Mar 31, 2026

crossing my fingers and toes....took the car on a trip this weekend. approximately 10 total hours of driving (plus more around town in between the trip up and back), 5 each way and nothing. hopefully the ford throttle body and accompanying electronics did it. time will tell. thanks to all for the advice and ideas. greatly appreciated.

07GtS197 · Apr 2, 2026

You jinxed me lol. My 09 p71 is starting to give me similar issues but I believe my problem is the cluster.

SnakeBit! · Apr 2, 2026

my cluster has been acting up lately as well, but it goes away. everything drops to 0 and once I get moving, goes back to normal.

07GtS197 · Apr 2, 2026

Mine does that too. It’s a common issue, the solder joints crack making intermittent contact. I used forscan the other day to run codes and a ton popped up, mostly from the instrument cluster so I know that’s the issue.

Todd in KS · Apr 2, 2026

Is there anyone that refurbs those? I was able to send the cluster from my wife's Tahoe to guy to get fixed for the same kind of issue. Had it back in 3 days. One of my kids has 2 panther cars so I anticipate that in the future.