Its been a long time since I got down and dirty with engines but this has me stumped.
I have a 90's 4cyl 4wd crew cab or what we call a ute. Truck has 250,000k on the clock , about 150,000miles. I love it and its been very reliable. It gets a sticky lifter now and again and has some horrific Timing chain ? or bearing rattle on start up but goes away when oil hits it and it heats up. I drive it very easy these days. early on it had terrible rattle/ knock/ piston slop/ noise at high speed, but was fine just chugging around. I seemed to cure that somewhat with higher octane fuel. Just recently it got sluggish and started to make the engine clatter under load, it was ok at low speed, low revs, no throttle. One day it just started running flat, no power if i accelerated over 2,500 revs or so (tacho is dead), like a plug was gone but not lumpy, not like a missing plug. Idle and start was fine, low revs fine. At the exact same time the knock / ping / detonation? became much worse, could not drive up steep hills without engine ready to explode, cant get much over 50k or 30 mph without bad clatter.
Mechanic tuned, replaced air and fuel filter, coil and accessories, plus and leads plus tune. (One plug, No. 4 seems to be running cold.) No better. May be running a bit cool, but today on the hill home the temp moved up, very unusual as radiator is recon. Not so rattleyfor 30 mins in morning, but afternoon home she's banging. will take it back to mechanic but ideas? carbon build up, octane, blocked injector , lean mix? I can hardly drive it and I cant stand the bus and train.Please help.
Thanks in anticipation. Will supply full details of model if required.
