Hey all. I'm trying to find out if anyone has had a similar problem to mine. My "service engine soon" light has come on. I took to the dealership and they replaced the knock sensor and I also had a "gross fuel evap" issue. Basically they said it was probably a bad fuel cap. I replaced the cap and they reset the computer. Light came on again a day later, replaced with a "factory" cap. Dealership said it has to be the cap because they could not find any leaks, they reset the computer. Light came on a day later with the same issue. They also said I should be burning Premium gas. My manual says 87 minimum, 91 minimum for supercharged model. Mine is not supercharged. I'm taking it in tomorrow. Does anyone know what might be causing this?

 

They got you for that knock sensor how much was that?; unless it was under warranty...
I have a 99 and my knock sensor sets off my engine light once in a while. Change your oil with the owners manual recommended oil weight. My truck has a little lifter rattle sounds like spark rattle but isnt. That will set off your light occasionally especially if it is the first start of the day. The other thing is I read something about an electronic device that controls oil pressure in your lifters that causes the rattle. Last but not least a guy I know has a truck like mine and his engine light comes on because of some fuel pressure error and he was told it was because if the gas cap too. From now on unless your truck is under warranty go to Auto Zone and get your diagnostics done for free and errors cleared out.

 

The knock sensor cost me $875, 650 of which was labor. I didn't have any engine noise or knock at all. After replacing 2 fuel caps and still having my light come on they found a fuel vapor valve somewhere in the rear that was bad causing the fuel vapor leak. They replaced the valve and also a filter canister for the vapor. The filter apparently leaked out some carbon pellets into my emission system which is now causing my light to come on again, I did see the filter and the pellets looked like mouse poop. Every time it comes back on I have to to take it back so they can blow out the lines and reset the computer. I'm taking it back again tomorrow hopefully for the last time. Tomorrow will be the 6th time I have returned to the dealership. By the way the valve and canister cost me another $450. They are not charging me to clean and reset the computer. It's been a nightmare...