QuestionQUESTION: Only 18mpg Highway, used to get 22mpg. City about 14mpg. 107k and have replaced plugs, EGR Valve, air filter, upstream O2 sensor, fuel pump and filter. Pump pressure at 49psi. No engine codes. Runs smooth, but doggy. Delayed throttle response. Old plugs were champion and were original. Back bank measured .60 Front bank .90 . New plugs autolite Double Plat. gapped at .50. 4 tanks of injection cleaner no improvement. Drove 3,000 miles on vacation no improvement. Any ideas? Thanks!
ANSWER: your plugs are the prob go put champions back in and gap them correctly. .50
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QUESTION: Please read Original Question CAREFULLY and note that the new plugs are autolite double plat. gapped at .50 per specifications and that the OLD PLUGS WERE Champions, and found to be gapped at .60 on the back bank and .90 on the front bank when removed from the motor. Vacation air temperature all above 90 degrees.
With cooler weather now in the 60s, gas mileage sometimes jumps back to normal 22-24mpg along with a major increase in power. Also when motor is at normal temp and sits off after running and then restarted, mileage drops back to 13-18 mpg. After driving 20 minutes on freeway, gas mileage with return to 22-24mpg. I believe this has nothing to do with the plugs, but with something else. No engine codes ever come up. I suspect engine coolant temperature sensor, even though it seems to be the same. What do you think?
Thanks!
Answerautolite double plat <----- prob Install champions only
U are reading that stupid little over head deal u know thats not real MPG right? This is only an avg with currant driving conditions have u done real math when u stop at a gas station full up all the way and drive until next fill take miles and divide by how much u just put in and thats is your real avg MPG.
