09 MCS... Cruising on the highway at 70mph and a 18 wheeler hanging out in the passing lane. I stomp on the gas to go around him and hit 100mph, but with the car bucking and check engine light flashing on and off. Then I smell something like a bad catalytic converter fumes coming into the car.

I slowed back down to 70mph and everything is fine. Check engine light is off, smell went away and drives normal.... Could it be a blocked Cat or is there something else wrong...

 

I romped on the gas again and got the check engine light to stay on, yeah.... So I went autozone yo get the codes read. Code P0300 multiple random cylinder misfires. There telling me the car needs a De-Carbon cleaning. Does this mean the valves need cleaning?

 

Yes, that what he means. Your car needs to have the intake valves walnut blasted. If you already have an air compressor, you can buy the tools necessary to do this yourself, for less than it costs to have it done.

 

Yes I have a pancake 6gal compressor. I was looking into doing this, but the guy I bought the car from told me he just did a valve job on the car. I guess I'll have to take the intake off and look for myself.... Thank you for confirming the walnut blasting. Is there a kit I can buy or do I have to buy parts from different companies

 

That little compressor may be too small, it may work , but it will take a long time to get the valves clean.
I bought my tools from Pelican Parts. Here is their how to page.

https://www.pelicanparts.com/techart...n_Cleaning.htm

 

Thank you!

 

Walnut blasting intake valves and new coils solved the problem...