Fuel problem?

[jus4kix03MM]

Im having a problem with the MM at idle and while driving. At idle it sounds like it has a huge cam in it. When I tap the pedal the rpms rise and stay at around 1500 for about 3-4 seconds before dropping back to idle. While driving at around 30 mph it stays at 30 with my foot off the pedal. I have to brake for it to drop the rpms. When coming to a stop rpms dont drop all the way until about a second or two after im completely stopped.
When I turn the key to purge the line it just makes a quick squeak sound. But the car fires up everytime. I replaced the fuel pump about 9 months ago. In the past ive had the fuel rail pressure sensor code thrown out. But once cleared the car was fine. Now the car isnt throwing any codes. Any help is appreciated. Thanks

[RF Overlord]

Possibly a bad IAC (Idle Air Control) valve. It's a fairly common issue.

The IAC is what controls the idle speed by allowing more or less air into the throttle body. If the PCM is commanding the injectors to put in "X" amount of fuel and the IAC is not allowing the correct amount of air, it can idle funny, or not at all.

You can try cleaning it, but that is generally a temporary fix. If you need a new one, I suggest genuine Motorcraft...other aftermarket brands seems to be iffy.

[RF Overlord]

Could also be a dirty throttle body. Mary's car had a build-up that caused the blades to stick and made smooth acceleration from a stop erratic. Be sure you use a throttle body cleaner that is safe for coated TBs...no carb cleaner.

[jus4kix03MM]

Thanks Overlord. But turned out to be a leaky hose that goes to the intake in passenger side. Replaced the hose and all back to normal.

[RF Overlord]

PCV hose? Yeah that's starting to become common, too... :up:

[jus4kix03MM]

Yes sir. Pcv. Caught me by surprise. It was the last thing i even thought was wrong.