Stumble at start-up

Hi all,

My '05 500 sits for days at a time. Lately, when it hasn't been started for about three days or so, when it fires up, the engine will stumble for the first few seconds, then stabilize and run fine.

This weekend, I'll take some electrical contact cleaner and shoot the MAF sensor, and pull the intake hose off of the throttle body and shoot some air intake cleaner spray around in there (not carb cleaner), to see if that cleans things up, but does anyone know if this is a sign of something starting to go out? TPS sensor, etc?

Air cleaner is good, fuel filter was changed at 30k, the car has 45k miles, and otherwise runs great.

Thanks!

GM cars would do that when the fuel pressure regulator would go bad. The pressure regulator (mounted on the fuel rail near the injectors), would let the fuel pressure bleed off the rail and it would take several seconds to build up enough fuel pressure at the injectors again.

I am not sure if the 05 500s have a fuel pressure regulator at the fuel rail or back at the pump?

On the older Tortoises the fuel pump has an anti-backflow valve. This little valve is supposed to keep pressure in the fuel rail and when it fails, hard starts are the result.
Ultimately, replacing the fuel pump is the 'right' thing to do, but most owners just get in, turn the key to 'on' but not 'start', then off. Cycle 2 or 3 times and THEN crank the car. This runs the fuel pump to 'prime' the fuel rail and get the pressure up before trying to run the engine.

I would assume the fuel pump in the newer cars is very similar.

Thanks, guys. I don't think it's a fuel pressure problem. It fires up on the first crank, but starts to stumble a bit after it's running, for a few seconds. I cleaned up the sensors, and it hasn't acted up since, so maybe there was some junk on one of them.

My 500 has been doing that lately as well. Thanks for the suggestions.

05 five hundred fwd limited 20k where is the IAC valve located? Im having the exact same issue about two times a week, any pics will help.