Stampede4ever

What causes this to happen, only on a few cylinders?

Thanks.

gMAG

iTrader: (1)

Is there a pattern...such as the rear cylinders? Or, are they random?

Stampede4ever

There are 2 on the rear on the passenger side, and 1 in the middle on the drivers side, the rest are clean.

Stampede.

LLLosingit

iTrader: (4)

One cause can be bad valve seals or worn valve guides. Oil will leak past the seal and down between the valve stem and guide then hot exhaust gases burn the oil off leaving a build up over time.
Fairly common on an engine with some miles on it. Bad valve seals aren't as noticeable on the intake side because the oil gets washed off by fuel as the fuel is pulled into the combustion chamber.

B52bombardier1

Certainly, wear on an engine can cause this. What do you run for fuel? Try running a Top Tier fuel such as Chevron, Shell or Exxon for a few tanks. They seem to have more and better detergents but yes, you will be paying a nickle or more per gallon for it.

Rick

G Atsma

If you can get Costco gas it is also Top Tier, at least in my area in Calif. Should be everywhere there's a Costco.

omc8

iTrader: (7)

Stampede , in our area the gas with the highest detergent is Shell 93 V-power , then BP 93 if you run regular it is in this order Exxon , BP then Shell. I only run Shell gas in all my cars. Right now V power is $2.90 gal , but pm me and I can tell you how to save Alot of money on Shell gas.

FCar2000TA

iTrader: (7)

I would put a can of Sea Foam in the gas. When that tank is down to 1/4, put Sea Foam in the oil. After 100 miles, do a top end cleaning with Sea Foam Deep Creep. Change oil/filter with a good full synthetic, and run top tier gas, as stated above.

Old Geezer

iTrader: (3)

100K on the engine? New? Race engine?
Leak down, and/or comp tests run?