Repost: 99 MERC SABLE - intermittent start problem

Another incident today. 20-minute drive; 5 minute stop; crank but no start. Disconnect battery for several minutes - no help. Tried spare key - no help.
Let car sit for 1 hour - started right up. ---< original post >----- Perhaps someone else has wisdom that can help. AUTO: 1999 Mercury Sable LS sedan, 24V, 58,000 miles.
ISSUE: Cranks and often ignites but idles at low (<500) RPM until engine dies.
OBSERVED SITUATIONS: - Drive car ~20 minutes or more on hwy and city. - Stop car for 5-10 minutes. Quick in/out of a store. - Return to car and try to start. - Car cranks fine, and engine may chug at low RPM, ~350. (The *sound* is similar to a flooded engine struggling to run.) - Repeat start routine, same condition. - Let car sit for 30-45 minutes and it starts and runs fine. - Three [now 4] events like this in the last 45 [60] days.
SUPPORTING INFO: - Main key ring has SpeedPass RFID stick, but condition occurs with and
without this set of keys. - Heat vs Fuel Pumps is known issue. I try to keep >1/4 tank of gas in summer. - When the car starts, it runs perfectly - smooth and powerful. - Dealer replaced Fuel Pump Relay after event #2; then event 3 occurred. - After events 2 and 3, no apparent error codes when connected to computer. - There was once a PATS system error discovered in the log. - I did not think to observe the THEFT indicator during these events. - After complaining of musty smell in climate control, dealer installed
"feature" that runs the climate control fan to help clear out the air chambers. - There have been four total events like this within 3 years. First event at 38,000 miles. No start, no fuel pump sound. Sit for 1 hour waiting for tow. Started right up - could have driven it onto the flatbed. Replaced fuel pump (not sure why).
QUESTIONS: - Has anyone observed (and solved) this issue? - Do fuel pumps behave intermittently or do they fail "hard" and not recover? - Any clue why time is my friend with this error? That is, what would change by letting the car sit for 30-45 minutes?
Thanks in advance! NZ
Posted to: alt.autos.ford and rec.autos.tech
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Did you try the 'clear flood condition' routine?
Hold pedal to floor while cranking.
If that doesnt work, THEN you pump the pedal while cranking.
Would help to know if either , and which, helps.
Assume in recent events you hear the fuel pump. - - - - - -- - - - - - - - - -
By the way, in future dont include 'other things' makes it hard to analyse.
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On Thu, 21 Sep 2006 13:28:25 GMT, Backyard Mechanic

OP can rule out fuel supply by monitoring fuel rail pressure. Now, the question is, can he spend a couple dollars for a Fuel Injection Pump tester ( fuel rail pressure gauge ).
I dunno. I have one but it screws _directly_ into the fuel rail ( no schrader valve supplied on my fuel rails, just bolts in testing ports ).
It is an analog gauge, but it won't lie when it comes to telling you if your system is pressurizing and holding steady. Thing of it is...it's on a short hose, and you can't drive around watching it, but you CAN GOOSE THE THROTTLE from under the hood and watch what happens.
Includes Flex hoses, fittings, and instructions
HARBOR FREIGHT Item # 92699
He can save himself a Lot of Trouble and time by isolating the problem. It could be an intermittent electrical connection to the pump, or something else, like a leaking vacuum hose.
Lg
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Maybe the ignition module?

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