I have an 2000 Exp(69K) and an 2001 F150(135K). Both of them have the knocking sound now. first it was just the truck but now they both have it. The CEL is not lit but they both run like crap now as well as get terrible gas mileage and have lost most if it's power. Initially I thought it was a spark plug problem but I don't think I would have the same problem on both vehicles.


I was thinking about buying one of these units (Actron 5138). Would I be able to get a reading of the condition of the vehicle even without the CEL being on? Does the OBD unit only pick things up when the CEL is on?

It's next to impossible to find a good, reliable and honest mechanic out here in San Diego that can troubleshoot the problem and find the actual cause of the problem without having to swap a bunch of parts.

 

Did you buy gas at the same place, at about the same time for both vehicles?
If so, it sounds like you could have possibly gotten some bad gas....

 

I usually get gas at a few different places but with the price of gas, I always put the cheaper stuff. I will try using the better gas and see if that helps.