I have a '97 Tacoma with 2.7 engine. Mileage is 217,000. Oil changed every 3000 miles.
I pulled these Split Fire plugs which the PO had installed and replaced them with Denso plugs and new wires.
Any ideas why plugs 1 and 3 would be so eroded on tips while 2 and 4 were not?
I performed a compression check on the engine while I had the plugs out with the following results:
#1 175 psi
#2 160 psi
#3 150 psi
#4 190 psi
#1 200 psi
#2 187 psi
#3 185 psi
#4 195 psi
I am wondering if compression tester that I am using is out of calibration as these numbers seem a little high.