Question about 2003 Ford F150 Regular Cab

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Ford f-150 2003 4.6 liter

At fast speeds its good it dies at lower speeds, changed the oxygen sensors and fuel injector and plugs still running rough and kind of lopping. It dies at stop lights saw the other guys talk about it what is a sticky IAC valve and how do I un stick it as I need to go to work

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I had a similar problem, check engine light would come on and all pointed to the mass air flow sensors and oxygen sensors. I was searching the internet to locate those little suckers when I ran across someone that said to check the little L-shaped rubber boot at the top of the engine near the firewall. I said what the heck, I went out and finally found it, I put my thumb on the hose and it was caved in. I put some pressure on the hose and it snapped in two. I drove my other vehicle to Autozone and they had a L-Shaped rubber hose with the same fit but bigger, so I cut it to size and I have not had one problem. I did replace another hose that looked dry rotted and checked all my vacuum lines to ensure that they were attached. This was over 3 months ago, I am not burning oil like I was and I am getting better gas mileage and the ride is superb. $7 for the hose. To replace all of those sensors would have cost me over $400. This may not be your problem but it would not hurt to check. Good Luck!

Posted on Aug 12, 2008

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Have u tried the map sensor?

Posted on Aug 09, 2008

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Rough idle in drive, correct rpm


Car idle is rough Inspection Service & Cost A rough idling engine can be caused by a number of issues, some of them are serious while others tend to be minor, but the symptoms remain pretty much the same. The car will feel rough and bouncy when the engine is running. The car will also idle below its regular speed, display inconsistent RPMs and may produce a shaking, skipping or slipping sound when the vehicle is running.
While a rough idling engine may seem to be a simple inconvenience it often indicates a deeper problem within the engine. The vehicle should be inspected and repaired as soon as possible because small problems have a way of turning into expensive repairs. How this system works: The idle speed of an engine is basically the rotational speed the engine runs on when it is un-coupled from the drivetrain and the throttle pedal is not being depressed. The idle speed is measured in the revolutions per minute of the crankshaft.
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