I recently bought a 94 2 door blazer and it has 107k on it .the guy I bought it from said it'd been sitting for 1.5 years since he got s newer Range Rover to drive around. He said the Blazer was borrowed from a friend who put in 87 octane and he said it started to have a knock .
So I bought it and we dropped the oil pan. All the bearings and caps were in great shape. We swapped the oil pump for a new one while down there. Oil pressure was always good.
I replaced the plugs and wires, all the fuel lines and a new fuel filter. We dropped the tank and drained the old gas out and put fresh 89 octane in it . It still has spark knock at certain tikes .most evident is when you are at a steady rpm while in park and do a quick rev. That is when it is the most frequent.
Also the trucks idle in park is around 900 but in gear (drive or reverse) it drops to like 300 rpm on the tach and feels very rough .
Any thoughts? No codes are being thrown .
So I bought it and we dropped the oil pan. All the bearings and caps were in great shape. We swapped the oil pump for a new one while down there. Oil pressure was always good.
I replaced the plugs and wires, all the fuel lines and a new fuel filter. We dropped the tank and drained the old gas out and put fresh 89 octane in it . It still has spark knock at certain tikes .most evident is when you are at a steady rpm while in park and do a quick rev. That is when it is the most frequent.
Also the trucks idle in park is around 900 but in gear (drive or reverse) it drops to like 300 rpm on the tach and feels very rough .
Any thoughts? No codes are being thrown .