Ok so here is the deal. I noticed my truck hesitating so I went ahead and changed my plugs and all of the coils. Well it ran like a champ for two days but now it is hesitating again. I finally threw a engine code for the IAT sensor, can this sensor make my truck idle rough and hesitate again? I had to order the part at oreillys should be here tomorrow. Has anyone ever had this problem?

 

First question, what kind of plugs did you put in? As for the IAT make sure the connector is on good before replacing it.

 

I replaced the plugs with motorcraft plugs. I checked the connections to the IAT sensor and they were secure, but it still put out a code.

 

What is the # of the code?

If the IAT is sending incorrect readings to the pcm, then it could be asking for more fuel as in cold start which would possibly cause some idle issues, or it could pull timing by thinking the temps are hotter than they really are.

 

generally default for the IAC is max cold if the sensor fails

 

Well I didnt write down the code, I know not smart, but it was the code for the IAT sensor saying that it was bad. So I ordered the part and it will be here tomorrow. So if the sensor is bad and is automatically set to default cold, would it make my truck run like it is?

 

yes you should also should check over the wiring for any chafing or rubbing that may have caused a broken wire

 

Ok good deal, I guess I will wait until tomorrow and pray that it fixes my problems. I appreciate everybodys input, maybe I will be able to sleep tonight.

 

There are no codes that say the "IAT is bad". Codes only indicate that the PCM is unable to get the expected value from a sensor.

FWIW, it you tested when the ambient temperature was under 50F, you will always get an IAT under-temp error since setup instructions were not followed.

 

Ok well I got my new sensor today, I disconnected mybattery, installed the IAT sensor. I no longer have the check engine light but it didn't fix my problem. The code was P0113. I feel like the fuel mixture is off. It doesn't idle too bad in park, but in drive, reverse it idles like crap. When I drive it it feels kike it is trying to catch up with itself kinda. It stumbles alot through first gear. The problem happens when the engine gets warm. When I start it up in the morning and start to drive there is no problem. Any suggestions? I'm out of ideas at this point.

 

I found this: http://www.obd-codes.com/

"A code P0113 may mean that one or more of the following has happened:

* Internally failed IAT sensor
* Faulty connection at IAT sensor
* Open in IAT ground circuit or signal circuit
* Short to voltage in IAT signal circuit or reference circuit
* IAT harness and/or wiring routed too close to high-voltage wiring (e.g. alternator
, spark plug cables, etc.)
* Faulty PCM (less likely but not impossible)"

 

Thanks ONELOWF I appreciate that, but I think I have narrowed it down to an egr problem.

 

What?

 

+1

 

Hardcharger - if you IAT fails open your CPU would interperet the outside air temp to be -40 deg F. Eg your mix would be super rich to account for all of the extra O2 at that temp. Your description of your mix seeming off is dead on. Check a couple of spark plugs. My bet is they are carboned up.