anti theft starting/stalling problems?

[radioiowa88]

My '99 Explorer has been having intermittent stalling/starting problems. Problem began with stalling while driving with ability to immediately start back up. Problem progressed to intermittently not starting after driving (usually after short distance trips) with start up after half hour then over an hour to eventually overnight. Now it is stalling while driving with no start up for several hours (I'm hoping it will start later!!). We've replaced the fuel pump/filter/strainer and new battery/terminals. Problem is intermittent with days to more than a week between problems. There are NO codes coming up at all. Stalling problems occur with no noise or warning. Start up problems occur with consistent cranking but engine won't engage. The anti theft light does start blinking rapidly during cranking. I've tried disconnecting battery to reset anti theft and have tried using spare key with no luck. Mechanic has no idea beyond possible anti theft issue. Others have suggested crank sensor. Any ideas?

 

[radioiowa88]

Update on no start

I tried starting the XLT 3 hours after the initial no start, but no luck. I went back again 5 hours after no start and it started right up. After some research, I did check the CE light in KOEO and it does come on, so I don't think it's the PCM relay. I should mention that the tach has been acting weirdly for several months, too-- working fine, then not working at all, then reading lower rpm's than what it usually registers. I haven't noticed any connection with the tach and times when the truck stalls or won't start, however. Is it possible that this could be connected or is it just a weird coincidence?

 

[Notoptoy]

Check the PATS System

Take a look at the dash when you are cranking while it won;t start. Is the THEFT light flashing rapidly? It's a good sign that either the key, or the transponder is going bye-bye. It's a $100 part, but FORD has to put it in and reprogram the system, mine was darn near $400! with the part and new keys. DON'T get conned into buying new keys! As long as you have two, you can re-program them yourself for half the price.
Try re-programming the keys FIRST. If you have two keys it's easy and fast, and outlined in the user manual.
Not sure about the Tach issue.

 

[b33p3rmcg]

Is it stalling only when you have your foot off the gas? Could be the IAC starting to act up. If the plunger for the IAC is sticking, it won't throw an error code.

 

[Smitty388]

99 Explorer Sport

I am experiencing the same problem. Started my vehicle & it had a rapid clicking noise. I thought that the battery was going dead, so I had it checked. The amp was reading in the 400's on a 850 amp battery. So, I replaced it. Within 5 miles, I started experiencing the same thing, and the battery gauge had dropped (even after getting a new battery). I just purchased a new alternator after the reading the current output of around 12 volts. My nephew had the same problem on his Ford truck and it ended up being a bad wire going from the alternator to the battery. I am currently troubleshooting the issue, so if anyone else has any input, let me know too!