2002 4.7 multiple missfire

[Cwy81]

Working on my father in laws truck, 2002 4.7, 266,700 miles. He uses the truck to pull a landscape trailer and mows lawns. Was fine until the 3rd stop yesterday then upon start up developed a bad misfire, check codes got misfire on cylinders 2,6 and a random misfire code. Asked when he had last done plugs and coils and he said never so we started there. Put all new plugs and coils in, old ones were absolutely whooped surprised it was still running. Got it back together started it up still ran like crap. Barely idles have to give gas to keep it running upon startup then it will sit and idle very rough very rich exhuast smell, popped up more codes. P0300 random misfire, p0500 vehicle speed sensor( didn't even drive the truck so thats confusing), p0304 cylinder 4 misfire, p0302 cylinder2 misfire, p0202 injector circuit open cylinder 2. Not quite sure where to start with this. Re checked 2 and 4 made sure plugs were tight and coils were on properly all is good there. Is the injector bad? Get a new one to swap out?

 

[jws123]

I would test the fuel injectors and puel pressure first. Other common issues are dropped intake valve seats if overheated even the slightest bit will cause random multiple misfires. Pull the valve covers see if it threw off any of the rocker arms another common thing is bad timing chains and guides could of skipped time.