The 1KZ-T in 93 KZJ-70 gives me a consistent 20mpg on the highway and around 19mpg in combined highway/city (and my figures are using U.S. gallons not imperial). It is mechanically injected and runs just great. This engine is bolted to a 5-speed tranny and moves around the 4300 lb Land Cruiser just fine, so I am certain it will be outstanding for a Taco.
My current project is taking the half-cut I just bought from mhooper @ jarco and making a KZJ-45 out of my HJ-45 Land Cruiser. I'll go from just over 90hp to up around 130hp and the torque will improve from about 155lb-ft to up around 210lb-ft--all with better miles per gallon. The 1KZ-T family of engines is fantastic.
Sparkplugs are Irrelevant.
Toyota: 1976 HJ-45; 1984 BJ-42; 1988 BJ-73; 1993 KZJ-70.
Dodge 1991 D250 Cummins;
BMW 1986 524td.