Rislone high mileage engine treatment added, possibly causing misfire/EGR valve failure

SINJON CHASE MCCREARY

MEMBER
2001 HONDA ACCORD
2.3L
4 CYL
2WD
AUTOMATIC
320,000 MILES

I purchased a bottle of Rislone high mileage engine treatment and added approximately a quarter of the 500mL bottle into the engine. I checked oil levels before adding to ensure I did not overfill.

I drove about 4 miles after putting the treatment into my car and then I began misfiring to the point where the car was shaking violently and the check engine light was flashing.

Assuming the treatment caused this (for whatever reason didn't agree with my engine) I changed the oil immediately and let it cycle through the car.

The car is still misfiring and I took it to O'riellys and had them test the codes. Shows misfire specifically in cylinder 3 and 4 and EGR Valve failure.

My theory is that there was so much built up sludge from over the years that it's clogged the EGR Valve? I'm going to clean it and see if it continues.

In the meantime and idea what's happened?

1 Reply

STEVE W.

MECHANIC
13,464 POSTS

If you added this to the oil that is not going to effect the EGR as no oil goes near it. So even if it did free up sludge it couldn't be the cause. However a faulty EGR could easily be the cause of the misfires and shaking. I would remove and clean the EGR and check the EGR passages as well. I could see this issue if you just used something like a top cylinder cleaner or a fuel system cleaner. Both of those can free up carbon and cause issues if the carbon gets into the wrong areas.