bought a 97 spyder 60psi #4 120psi 3,2,1,.new motor on the way.how difficalt to remove from car?.does it come out from above or out the bottom?.78,000 miles on motor car is like new,not one mark inside or out.#4cyl.has score lines as though a ring is broken.kept showing code po505.dealer cleaned throttlebody and intake.installed a new iacmotor.92 miles on came the celight.any thoughts?

 

What is p0505? Take it back to the dealer.

 

po505 is idle air control motor.cause,s unstable idle .a $325. dollar part.located underneth the throttlebody.obd2 meter indicates a problem in the wireing harness at the motor.shoes a miss fire on cyl #4..$1100.and I still have the same problem.

 

This sounds dumb... but did you do your 75k mile work? Head gasket, T-belt etc?

 

Sounds like a bad ring land in cyl #4. An easy way to check it is to add about a cap full of oil into the cylinder and re-do the compression test If you see an increase in the pressure then its the ring lands. If not then it may be the valve seals or the head gasket. A leakdown test will tell that