I have an 2005 Endeavor LS AWD that starts some times and the has trouble or won't start. It cranks fine, but won't turn over. Original symptom was that my wife said the car shut off at a stop light, but she was able to get home. I performed all the troubleshooting below, then noticed the car just started starting up again after some days (hence intermittent), but would have a little trouble idling. I figured it would adjust and seemed to, but then had trouble turning over again until I floored the pedal, then it started and I was able to drive. Seems to stay started just fine sometimes.

Here's my troubleshooting so far:
-Battery is good, when I get's low, I charge it again and the car cranks fine.
-Battery get good volts before and after starting.
-both relays are good. I tested for continuity and clicks
-Fuses are good
-Fuel pump is a tough one. I can't hear anything from the gas tank (at cap or under seat) as some describe, but when the car is started, it can idle okay and drive just fine.
-Replaced the air filter, which was filthy and might've caused the original issue. A while ago I noticed some dumb mechanic tried to hammer the filter compartment into place. There was a hammer head size opening (more like a cut than a hole) in it. The car ran for YEARS like this. I finally covered the hole on both sides with gorilla tape. It's sealed again and I will monitor it.
-On another forum, someone said to test for power to the fuel pump at position 4 & 5 on the plug. I get nothing here, but do get full volts at other positions on the plug, so I assume the info is bad and the plug is fine. Again, pump works.
-I'm thinking the MAF sensor, but want to be sure (expensive little sucker).
-That same article referenced testing volts to the throttle body sensor, but the article was so old that test procedure document isn't there anymore, so I don't know how to test it.

Any ideas?

 

You need an obdII tester ELM327 is $10.00 eBay.
A bad map sensor will prevent car from starting. Just unplug it and car will run albeit roughly. A crank sensor will give intermittent issues. Make sure it's clean and not broken or a wire to it if it's on the crankshaft pulley otherwise it's recessed into probably a position on the front of the motor- there are particular resistance values for every sensor so could easily be tested if you can find the values and Che on the sensors with ohm meter or voltage meter when it's running.

i suspect a fuel pump or timing belt issue but don't replace parts until you get the OBDII ELM327 tester and always check the connections for corrosion and almost broken wires, and get a Bluetooth ELM327 supposed to works good with android tablets and phones.
Good luck.
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