my trucks been running rough for quite some time now its an 88 f250 4x4 351windsor. the codes i got with koeo are, 10, 29, and 31 and koer i got 21, 31, 77 now theres no egr valve on the truck the person who had it before me put longtubes and a block off plate but left the evp sensor plugged in. i went ahead and ordered a blockoff plate and an egr delete thing you plug in to trick the ecm from rjminjection. you think shell run better after i install these? the code 21 said ect out of self test range should i also replace the ect? any helps greatly appreciated.