You are correct sir

 

that would make sense considering i might have burnt off oil when i was driving becuz i smelt a burning smell off the engine. which i beleive was oil

and im assuming it doesnt help that i learned to drive stick on this car? and ive stalled it a few times?

 

The evap will knock on these cars , it actually sounds like someone is tapping on your trunk lid .

 

wow now i kno what the tappin in the truck is hahahahaha i thought i was just crazy hahaha

o ya whats the evap haha

 

well i dont know if its from the trunk or the engine so i dont know yet but other then bad gas what else could the knocking be and its only when i start the car and it happens randomly

 

it requires 91, some states only have 89 or 93.

 

ive put in 93 since then. ive had it for 2 weeks the first week and a half it had regular now its on premium just wondering if the knocking is from that? and if so should it subside soon?

 

Yeah, I didn't think it was the fuel. I'm not familiar with the SS/SC recommendations, but if you're NOT running any kind of tune on a TC, it states you can use regular and premium is recommended. If it sees you're running regular it just won't advance timing as much and as the manual states "...but the vehicles acceleration may be slightly reduced".. "If you are using [regular] or higher and you hear heavy knocking, the engine needs service" (Page 5-5).

I'm in Houston and although it hasn't been that hot here since I bought the car I've run regular several times with no issues whatsoever. I've got 0* KR with any fuel I've burned in it and it has always been that way.

On that note though I'm planning on sticking to premium come summer time. Sitting in traffic, sucking 100 degree-plus underhood air into a turbocharged engine is probably flirting with the devil. The intercooler surely helps, but stop-and-go on an already hot Houston summer day will probably cause heatsoak on it and make it less effective anyway.

Wow, I got off topic there. Bottom line: I don't think it's the gas.

 

so any ideas on wht it might be then?

 

My vote is oil is leaking into your cylinders when it's sitting there. That's why it's common for older vehicles to smoke a little for a minute or two when you first start them and then it clears up.

 

ok so price to fix it? estimate just a rough guess?

 

It doesn't require it, unless you interpret

"Premium recommended but not required"

to mean something else.

 

I'm not sure. The car before the Tahoe that I owned wasn't worth fixing, so I never got it fixed. I'll have to ask. My uncle's an aviation mechanic and car collector, so he'd be able to tell me what probably needs to be fixed/replaced at least. He's the one that originally pointed it out on my vehicle.

 

i just gotta find out soon because i got 90 days for **** to go wrong on my car so the dealership can fix it

 

nothing is wrong with the car... thats my official diagnosis

 

Alright, I got the low-down on it. There's a possibility that your valve guides are worn and oil is getting past them and dripping into your cylinders when your car is sitting.

It shouldn't cause harm to your engine, it's just one of those things that happens if you have a high mileage on your car or if it's old. It's usually one of those things that isn't worth fixing due to the benign nature of it and the cost/complexity of getting it fixed, since you're going to have to get to your valves to fix it (if that is indeed what it is).

I'd keep an eye on it and figure out if it could be consistant with that or if there's something else going on that may lead to something else being what the problem is.

 

big difference between regular and 89 as mid-grade usually tests around 91 depending on the pumps, everywhere will be different

 

If your vehicle has the 2.4L L4 engine (VIN Code B)
or the 2.0L Supercharged engine (VIN Code P), use
premium unleaded gasoline with a posted octane
rating of 91 or higher. You may also use regular
unleaded gasoline rated at 87 octane or higher, but
your vehicle’s acceleration may be slightly reduced,
and you may notice a slight audible knocking noise,
commonly referred to as spark knock.

You didnt finish the paragraph lol it doesnt make it seem that bad in the manual

 

It IS bad though.

 

it hasnt happened in a while and im just gonna think it was the evap thing

 

When I bought my 2.4, the dealer filled it with 87 (regular here at 3500 feet elevation), I ran a couple tanks of 92, then tried a tank of 87 again. Noticed very little if any difference in mileage but it would knock like a bitch at low (under 1500) rev's with the 87. I will stick to 92 thanks

To the op's topic, it is easy to tell if its detonating.....if you get on it at low rpms in a higher gear (4th or 5th) and it sounds like someone dumped a load of marbles down your intake, it is detonating....get off the throttle before your pistons look like the pix above and get some higher octane into it.

 

i say, run 87, cause **** if i care if your motor blows cause apparently the guy that builds motors regularly doesnt know his ass from a hole in the ground

 

ok thats not what this thread is about its about me putting 2 tanks of 89 through the car and now im putting in 93 and i heard a total of 3 sets of 2 knocks which i now think is the evap thing