Hey everyone. My 91 4.9 has 226k on it and as far as I know every sensor is the one from the factory. Truck still runs like a dream and idles fine. My question is what all sensors and stuff go bad and which ones should I replace?

 

Well, if none are bad, then none need replaced lol. Don't fix it if its not broken! You can clean the iac and egr valve and throttle body if your itching to clean it up some. But if none are bad, then none are bad.

 

If you have an issue and have to replace anything try to get the Motorcraft replacement, these trucks are sensitive when it comes to that I've found. Be prepared to pull parts at your local pick and pull yard if you're thrifty like me.

 

How do I go about cleaning the egr valve? I've already cleaned the IAC. My truck burns extremely clean though I recently changed my plugs and wires and they hadn't been changed in a long time and they looked brand new.

 

If it's working let it be. To clean the EGR you need to remove it, that may snow ball if things are rusty. Sounds like you have a good running truck, and I like that you want to do preventative maintenance but I would just leave it be.

 

Ok I won't mess with anything until my truck messes up lol. Thanks everyone.

 

Pull codes to see if they all work.

 

I need to get me a obd1 code reader.. My check engine light bulb is burnt out.