Intermittant knocking and smoking
I have searched this forum and have not found anything like this. Any help will be appreciated.
I have a 1994 Mazda/Ranger with a 3liter engine, automatic transmission, 2wd, towing package, 185,000 miles and generally it runs great.
I commute 22 miles to work and when I stop at an intersection 14 miles into the trip and then even with light acceleration the truck knocks severly and a cloud of light smoke comes out of the exhaust. It will not knock or smoke after this point even with full acceleration. I have tried slowing down before this intersection and accelerating and it will not knock or smoke until I have driven about 10 miles. At this point I can accelerate twice and it knocks and smokes and then it will not knock or smoke again.
To simplify, it will not knock or smoke until I have driven about 10 miles. If I slow down and accelerate twice it knocks and smokes and will not do it again. If I stop once and then accelerate it knocks and smokes worse and will not do it again. If I stop the truck and turn it off before it knocks and smokes and then crank and continue the trip it will not knock and smoke.
I have had the cooling system pressure checked hot and cold to check for a blown head gasket.
If you have any questions, let me know.