Adamtd101

This is my first post- I was reading some posts about people having to replace/diagnose knock sensor problems and have one of my own. I'm not very familiar with stuff under the hood but I'm always happy to help with electrical issues inside the car. I used to install car electronics professionally and still know many wire diagrams by heart so I'm happy to help in that area.

Right now my car is at a mechanic's garage, one that I don't know well enough to trust, but I think they know what they're doing because they replaced my heater core a few weeks ago (at a hefty cost of $600) and my car seems to be put together properly. Anyway, I had two codes come up and one was the knock sensor and I need an inspection. They called me and told me that it needed a few things, one being a new knock sensor but after reading some other posts I'm uncertain about a) that it isn't the MAF or something else and b) that it's worth repairing at 4/5hrs labor ($65/hr) in addition to the 2hrs they've already charged me to diagnose.

I thought it was pretty standard at places like Midas to charge a flat fee, like $50 to diagnose, but these guys are saying that something like this it's as long as it takes to figure out what all my car needs. Basically, they told me everything it needs to pass inspection so after I give the green light to fix it (and drive it to get rid of the service engine light) they'll put a sticker on it.

I am going to my hometown in about 2/3 weeks where I have a friend who is a mechanic who I trust and I know will give me the best deal, but my question is how do I make sure it needs replaced, and how much labor should that really be? I can get a factory part online for about $150 and that's $35 less than the mechanic can get it from the dealer for. Is it likely that the mechanics would know for sure it's the knock sensor that needs replaced? That's what they've said but after reading a lot of different threads here I'm second guessing how sure they are about it needing replaced.

Also, I'm thinking these guys are ripping me off but I can't be certain. It seems like the fact that they said 'bring it in and we'll see what we need to do' and they looked at it officially from 2pm-4pm and called me with what it needs and are charging me for that 2hrs labor on top of whatever work they're going to do, makes me not want them to touch it. Especially since I wasn't expecting a $130 diagnosis fee. Thoughts?

Is it harmful to go a few weeks until I make the 8hr drive home to my mechanic before fixing the knock sensor if that's what it is?

abmobil

The knock sensor is a very common problem on this engine and you could make that trip 10 times with that bad sensor and the truck will be fine.
My dads 01 sc crew cab had a bad knock sensor for like 30k before he got it in to change it.
It did cause the ecu to dump boost and it was making less power but otherwise drove fine.
My friend has had a 97 infiniti I30 for over a year and the the knock sensor code has been in there since he got it but it drives excellent.
When nissans need knock sensors they dont throw the engine light but they do store the code.
$130 for a diagnostic that took them 10 sec to hook the scanner to the truck and pull a code is insane.
I would drive to your hometown mechanic and not worry.
Dealer diagnostics are an average of 90 bucks and most shops charge 65.

Adamtd101

thanks for the input. I don't know what to do about the 2hrs they spent looking at it yesterday, because when I dropped it off I basically said that I wanted them to check the codes they found last time I was in and see what needs to be fixed. When they called me, they basically went through a list of things my car needs- including a wire that was cut or something that stopped my horn from working (which I knew, and could've easily fixed myself but they took the liberty of fixing that while it was in the shop). I was like, thanks for fixing that, and then I realized that they're actually charging me for whatever time it is in the garage, and they looked over the whole car for whatever reason- probably because I told them it needs inspected after I get the service light stuff taken care of. Either way, they have no right to charge me for all that time when all I asked was for them to look at the service light and tell me what I need to fix. The time they spent looking over the rest of the car should fall under the price of an inspection if that's what they did it for right? That's like $21 here in New York. I don't know how to go about telling them this though, the main guy seems to be a nice guy but he wouldn't give me a break on any labor at all and he is the type to give estimates under the pretense that it could be more or less depending on how much time it actually takes- so he's not sticking to his estimates anyway. That's hard for consumers to feel good about because basically, a slow mechanic only costs you more money.