My CE light on my 97 F150 4.6 4X4 Auto has been on for about 6 months. The truck runs fine. It does idle high when cold (seems higher than normal) but returns to normal when warmed up. When idling in park the engine surges (AC Off) from 800 to about 1200 rpm. I had the codes read and there are as follows: IAC overspeed error, Catalyst system efficiency below threshold, and system too lean.

I have checked the IAC sensor with an ohm meter, it is within range at 10ohms.

Anyone have any ideas??

 

Clean or more likely replace the IAC valve. (IAC overspeed). Very common

Check for vacuum leaks (lean). Very common.

Cats are worn out. (below efficiency" Very common.

Next time, take your code(s) and use the SEARCH feature for archived posts that discuss them in depth.

Also, try to get the exact code numbers, not the descriptions. Use the numbers as your SEARCH keywords.

Steve

 

I have a 2004 F150 with 28K on it. I took it for some 30K maintenance, and because the Check Engine light was on. The truck stalled numerous times at idle, within a short period, before this light came on and stayed on.

The dealership states that the code is coming up for a Temperature Control Sensor, which is covered under warranty, but that I must clean the Throttle Body first, or this sensor will keep blowing. The SA stated that the truck will continue to stall unless I get this maintenance done, and that they will not replace this part until then.

I do not think that this correct, as I do not see Throttle Service as a maintenance item, unless I am missing something. Shouldn't they clean the Throttle Body, when they replace the part. Does the warranty put time in for that?

I also had Emission service, Transmission service, and replacement of the fuel filter done.

What is your opinion?

Thanks


2004 F150-8FT