98 ultra misfire and knockish sound after running 87, low oil life I know it needs a change and I'm gonna change the super charger oil

[Vwguy98]

I put 87 in by accident a week after purchasing this 98 Buick park Ave ultra with a very pleasing supercharger, and I've been told it reguires 91. The day after it started missing and has ran like that for the past few days, it also is making an almost knocking sound. I placed my hand on this intake, and on the charger and it feels like a little hammer inside my charger, but a slight tremor when my hand is on the intake. I know it needs an oil change, I know it could probably due with an oil change on the charger tho it's a sealed on from what I've read. I want this car to run right, amy clue what I could have done with the 87, or if that's just coincidence and not truly dangerous enough to cause these kind of things? Help😭

 

[MelsRegal]

Is the tank low enough to put some 93 octane in?
Do you have a check engine light on?

 

[Vwguy98]

Is the tank low enough to put some 93 octane in?
Do you have a check engine light on?

I put 40 dollars of 91 and octane booster in ontop of that. Flashing cel, I took it to a reader and it said drivers 3 5, and mis. I don't understand the first one

 

[Vwguy98]

I put 40 dollars of 91 and octane booster in ontop of that. Flashing cel, I took it to a reader and it said drivers 3 5, and mis. I don't understand the first one

Dash is flashing change oil as well, I know I need to do that

 

[MelsRegal]

I put 40 dollars of 91 and octane booster in ontop of that. Flashing cel, I took it to a reader and it said drivers 3 5, and mis. I don't understand the first one

Codes start with the letter P followed by usually 4 numbers. You need the real code not what you posted.

 

[HotZ28]

it also is making an almost knocking sound. I placed my hand on this intake, and on the charger and it feels like a little hammer inside my charger, but a slight tremor when my hand is on the intake. I know it needs an oil change,

Apparently, you have worn out S/C coupling. An oil change will not help repair that worn coupling. The snout has to be removed to replace the coupling. Miss-fire is another problem altogether. You need to have a good scan tool to determine what cylinders are miss-firing.

 

[Vwguy98]

Apparently, you have worn out S/C coupling. An oil change will not help repair that worn coupling. The snout has to be removed to replace the coupling. Miss-fire is another problem altogether. You need to have a good scan tool to determine what cylinders are miss-firing.

I'm gonna look into that coupler after some well needed sleep and hook up a reader, this is my first s/c vehicle, going the charger isn't too temperamental😂😭

 

[Mad_Coachman]

How many miles?

 

[BuickGirlFromMars]

I put 87 in by accident a week after purchasing this 98 Buick park Ave ultra with a very pleasing supercharger, and I've been told it reguires 91. The day after it started missing and has ran like that for the past few days, it also is making an almost knocking sound. I placed my hand on this intake, and on the charger and it feels like a little hammer inside my charger, but a slight tremor when my hand is on the intake. I know it needs an oil change, I know it could probably due with an oil change on the charger tho it's a sealed on from what I've read. I want this car to run right, amy clue what I could have done with the 87, or if that's just coincidence and not truly dangerous enough to cause these kind of things? Help😭

The coupler likely saw some pressures from the knock and was weakened enough to need replacement now more than ever. I do suggest not driving until you fix your coupler or snip the belt(if it needs a new belt snip it, if good… uh.. take it off. Good luck. )

if you remove the supercharger from the equation you will quickly know if valvetrain Or lowers something internal on the rotating assembly. You don’t seem to have that. But if noise is gone you know. If noise persists, cut power to each cylinder 1 at a time by pulling the wire and starting with it not able to ground out on something
The misfiring cylinder or damaged part will reveal when the noise and feel is only choppy not clacky from worn parts the bad chl8nder likely makes very little power if it was the case, so you would not notice a big difference in load.
But I think coupler is a great place with 2 bottles of gm supercharger OIL only. Don’t use any other supercharger oil because gm is the cheapest rebadge of the oil even their own and it’s also in nice convenient packaging. It’s not the whole 2 bottles so that is why you need two. A couple is an EASY job once you remove the snout and it’s bolts. Just 10mm ones too. Fix the vacuum t under the snout as preventative while under it

torque the snout to specs,too, it’s machined pieces so a fiber gasket if you pull one off is a good idea but if it was flat metal, I would just reinstall without a gasket. Mine was this way. No leaks.
Also verify your boost bypass valve is functional and has good vac source. And solenoid works.

in the end, send us some damn pics no want to see your engine. Just a top aerial view is needed