I recently had my water pump, timing belt and radiator replaced, they also did a tune up. Upon picking up the truck before I get home ( less than 2 miles) the check engine light comes on. The light was never on before I took it to the Repair Shop. I take it back to the shop they say it is coming back as the Knock Sensor. They say that nothing they worked one would have caused this problem and say I will have to fork over more money to fix it? My question is this, is there anything they could have done while doing the above work to cause this problem?

Thanks

 

Also the light comes on after I drive for a few miles not when the truck is first started, but there have been times when the check engine light does not come on at all.

 

hmmmm base on what you have specifically mentioned, nothing would have had an effect on the knock sensor wire. (That's the culpril most likely)

What did they do tune up wise?

Changing the KS sensor and wire out is child's play - well a mechanic's child's play! lol Pull the intake plenum the fuel rails, then the lower plenum and youll have access to the KS and KS wire.

 

They did the standard tune up stuff, change oil, change spark plugs, etc.

 

I cant see how any of that would have done anything to the KS wire honestly. Look below the TB for a long black plastic cylinder (which is a wire connection) btwn the wiring harness and the lower plenum. pull it apart and look at hte connections, if they are corroded clean em, it may help.

 

Can you explain it in more detail for me? I looked in my Haynes Manual and can't find any mention of the Knock Sensor at all. When you say look the below the TB what is the TB, sorry for my ignorance.

 

I do believe that connector for the KS is right next to the center driver side fuel injector. You should be able to see it just below the plenum (aka air intake chamber)