Drove through some water, now won't idle right

[Wastelands Warrior]

I got stuck in a situation yesterday where I had no choice but to be a dumb --- and drive through some standing water in my 91 Spirit R/T. I plowed through and made it ok, but car didn't want to idle afterwards. Figured it was just due to the moisture so I drove it about another mile to work, and car was running fine. No loss of power or breaking up. I got into the parking lot and tried to get car to idle. Wouldn't hold an idle but would fire right back up if I pressed the gas pedal to the floor while starting. Worked my 8 hr shift and came out and car fired right up, but again wouldn't idle. Got out to the highway and drove 30+ miles home, with no probs. Power was fine and got into boost no problem. Got up to 90 mph a couple of times with no problems. Came home and parked it for the night. Went out before and it's the same deal. Idles erratically low and won't hold. Have to put foot to floor to start. Got out on the highway and she's a beast. Have no check engine light or codes. I get stupid when my cars don't run right and I don't want to just start throwing parts at it. Help!

[looneytuner]

Give it a day or 3 to dry out or hit stick a box fan under the hood to speed up drying

[Force Fed Mopar]

Water in the engine harness connectors maybe, or maybe the IAC motor acting up.

[sdac guy]

Just a note about what you are doing. During cranking of the motor, the throttle MUST be left alone as that is when the ECU checks to see what the idle reading on the TPS is. So if you are holding the throttle open, then the TPS is sending that current reading to the ECU telling it this is the idle reading.

That may be the reason it won't idle when the throttle is returned to actual idle position. As now the reading is way lower than it was when cranking, and the ECU is confused as to what to do.

If the engine will not start with the throttle at actual idle position, that is the first thing you should be troubleshooting. Possibly the IAC motor is all the way closed to try to compensate for the large amount of air the open throttle allows. So give it a few tries to start. You may need to disconnect the battery to let the ECU start over on learning what is actual idle conditions.


Barry

[Wastelands Warrior]

Thanks guys. Working on it now.

[Wastelands Warrior]

Replaced IAC and she's running good again. :)