No. I have always gone by the Owners manual and it says regular. I buy only Mobil and I think it's maybe 87 octane?

 

,,,,,,

 

lol... at least 2 inquiring minds still want to know.

 

Sorry, I DID miss that question!
The short answer is, I do not think so.
2 years ago I had water pumps fail TWICE in the space of a few months. Consequently, I am still paranoid when I drive, so I frequently look for changes in the gauges and the CHECK GAUGES light. The CHECK GAUGES light has only come on 3 times in 14 years-both times for the pump and last week when the battery/alternator gauge dipped below 9 (the actual reason I took it to the dealer and not the engine knock).
But having said that, it's possible I have not noticed if the oil pressure dropped somewhat, but not enough to trigger the CHECK GAUGES light. The knock has been hanging around so long and is so sporadic, that I cannot honestly tell you if I am ever concerned enough to look at those gauges.
But now that you've told me to look out for this, I will. I live in south Florida and it's very hot here the last 3 days--above 90. I drove it yesterday for at least 20 miles and the knock has not happened, even when I got caught in some heavy traffic and it was idling and the AC was on with the high heat outside.
It WILL knock again, however. It always does.

 

On your next drive, take something to write with, or take pics of the oil pressure gauge. Make a note of what the reading is at cold engine idle, and the highest reading once you're immediately on the road with the rpm's up. Then check the same two readings once the engine is up to running temperature. The reading differences between hot & cold, and idle vs high rpm's can be helpful to determine the health of an engine.

 

That's an excellent idea. I will do it either today or tomorrow. I'm going to try and schedule an appointment at a shop for later in the week to have the exhaust system checked, as you suggested. I found a highly recommended Speed Shop close by.

 

That's great to hear. Not saying the dealer is definitely trying to take advantage of you just because you're a woman, but they might be (not trying to be sexist) lol.
The more you can arm yourself with knowledge when you take a car in, the better. They may get the idea that you're not a pushover.

 

I try to go in armed with everything I know about the car. And I have records that go back to the day I bought it in 2002 and when they ask me a question or say, well it's probably the idler pulley or whatever, I can immediately answer, well okay but that was replaced on March 12, 2015.
I never act like I know something when I don't. When I got a diagnosis of a "blown engine" in Jan. 2015 by a mechanic I did nor know, but was recommended to me by someone I thought I could trust, I made him put it back on the lift and I asked him to show me exactly what he was talking about. He did not seem thrilled to do it and said, as he was showing me, do you even know what you are looking at. I did not get my back up and I smiled and said, as I snapped pix with my phone, "Well, I have been under this car before and I do know how to change the oil because my Dad was an auto mechanic. But, the truth is that in my job I deal with the GM engine plant on Tonawanda. Where they make the engines for the Chevrolet Silverado and Corvette Stingray. I called the engineers I deal with and told them what you said about their engine and they asked me to take pix".
He backtracked and said maybe the engine wasn't really blown and he did have the guts to admit he did not want to work on it and that's why he told me he "thought" it was blown.
Turned out that all it was a rear main seal leak. Once it was fixed, the car did not leak a drop of oil.
I am polite to the guys at every shop I walk into, even when they are not so nice to me. I always pay cash to the independent guys, telling them that my dad owned a shop (he's been gone over 10 years unfortunately) and I understand cash is king. I really only started using the dealer because I had the good experience with the rear main seal job--BUT, that was after I had the Controls Manager at the GM engine plant call the service manager!

 

I say that couse my lt1 95 hand book said 93 octane min that I could try lower octane but may get kocking ,an this is bit more then your average engine ,an 87 is not allways 87 ,I allways ran something above with any thing that was to be a high performance engine ,I know the compression ratio must be diffferent from my old lt1 to the ls1,at the ls1 forum they talk about 91 or higher ,I run 93 an near everything except my base wich I run it few times a year ,I run 93 in my lawn mower of 12 year ,its got a better shelf life ,so though it may say 87 in the book there is a lot of thought that running anything below 91 may not be good ,that was one forum another one says a guy ran 87 an got knock sometimes try running 93 for awhile see if it goes away ,cant hurt

 

I have an update to the mystery of my collapsed lifter diagnosis. Over the past 4 days I have been unable to get the engine to knock the way it did at the dealer. To be fair, as I have mentioned, the knock has been very sporadic over the past year or so and it might be weeks before it suddenly happens again.
I tried all sorts of speeds and driving conditions and it sounded fine.
Oil pressure--it always hangs around 40-45. If I am sitting in traffic idling, it tends to drop to 40, but never below that mark. Higher speeds make it go up closer to 50, but mostly around what I think is the 45 mark.
The SES light that I have always mentions comes on occasionally with the P175 and P172 codes has not been on in a few weeks and it has not come on despite driving it a bit more than usual.
I've proven I am no mechanic, but it seems to me that if the lifters collapsed and were flopping around, they would make a consistent noise. That's not the case. I could turn it on tomorrow and it might be there, but so far, the engine seems quiet.
I tried to run some gas down in my travels (I had a damn full tank going into the dealer last week) and as soon as I can get it to half, I will try a higher octane gas.
I had a 94 Z28 that I only ran on the good stuff but when I bought this car, the 2002 model with pretty much the same engine, the dealer told me to use regular because high test would make the engine run hot. I actually WROTE IT DOWN on the receipt from my first oil change-with the name of the service guy that told me!
I've done some research since reading the recommendations on the board and I am now less sure that advice was correct. Anyway, I don;t see any harm in buying a better grade of gas. I don't know what my gas mileage is, but I sure don;t buy gas very often since I put it in semi-retirement last year.
So now I am really stumped. Do I ignore it until it starts knocking again? Do I take in and have the MAF sensor checked as it relates to the old codes?
Or, do I take it to the speed shop and ask them to check the lifters (which might be an open invitation to tell me something is wrong)?