fender1983

Problem #1:

It looks like a very often problem when vehicle stalls at idle, usually after acceleration. I changed IAC on the weekend, no difference. Suddenly from time to time idle drops to 500 rpm.

No issues during acceleration (almost, see problem #2).


Problem #2:

During mediocre acceleration if you get above 4k rpm the traction controls kicks in and cut the fuel off. Happened to me about 3 times last week. I am sure I didn't loose traction and didn't hit a bump.


Any ideas?

cliffyk

#1: Is it stalling, or just dropping to 500 rpm?

#2: There are many reasons this may happen, though that it is happening intermittently makes diagnosis difficult. It could be an intermittently bad fuel pump or fuel pump driver module (monitor the fuel pressure and see what it is when the all is hit), or a bad charging system/battery (monitor battery voltage, check the terminal connectors and grounds), or any of several other issues.

Also it is likely not the t/c kicking in but rather what Ford calls Failure Mode Effects Management (FMEM). This mode activates when one or more sensors are not providing valid information, or if engine overheating is suspected.

FMEM substitutes default pre-programmed values for the data that should be coming from the sensors, and in the event of overheating limits spark advance and engine power/speed to make the engine run cooler. A bad ECT sensor or bad wiring can make the PCM think the engine is running hot.

Data logging while the problem is happening would reveal a lot, also scanning for pending DTCs and reviewing freeze frame data may reveal something.

fender1983

#1 it was stalling until I replaced IAC valve. Now it drops to 500 rpm, and after 10 seconds goes up again.

#2 Got a new high output alternator and battery. At idle I am getting 14.3V, if it goes to 500 rpm, than I am not getting enough rpm's on alternator and I am getting 12.7 V (same as battery).

#3 Usually when fuel pump goes bad there are no thrust during acceleration. It happened to me before on different vehicle.

Thanks for the information regarding traction control.

cliffyk

Did you disconnect the battery for 5-7 minutes after installing the new IAC valve? Doing so will reset the KAM and force the PCM to relearn the idle air trims.

I actually do this 2-3 times a year as the seasons change to let the PCM relearn all the adaptive learning stuff...