My longtime friend has a 97 scab 2wd 4.6 auto w/ 130k. Everything is bone stock. He started to notice a decrease in his mpg. Did a complete tune up. Plugs, wires, oil/filter, air filter, fuel filter, seafoam intake and tank. And mpg's have gotten worse. No CEL, runs and drives great. while discussing the situation I asked him what kind of plugs he put in and he said they were MC copper plugs. Would this be some or all of his problem?

 

Oops! you'll have to forgive me. I posted this in the wrong place. I'm doing this on the mobile version and I guess I fat fingered the wrong section. LOL

 

Change the front O2's.

Clean the TB

Clean the MAF

Ensure the cats are healthy

Check parking brake for drag.

Check engine cooling fan clutch operation

Check to ensure tune is going into closed loop

Check to ensure the tranny TC is locking

...anything else suspected of introducing parasitic drag

Etc, etc ... just some ideas - after the low-hanging fruit are dealt with you may need to have the truck fully diagnosed ( A/F's, fuel trims, EGR, etc)...

See the tech Articles section for more info on some of these procedures - or simply search the site ...

It ain't the plugs, and Seafoam will do SFA and may actuallly pecker the O2's and cats. The stuff is highly misused crap and not suitable for use on an engine with a sophisticated engine management system - there are better and safer alternatives to decarbon an engine (again it's all here for the [Advanced] searching).

Good luck.

MGD

 

The copper plugs shouldn't cause problems, but they are not going to last anywhere near as long as the platinums.

I'm leaning toward worn out lazy front O2's. Only use Motorcraft or Bosch on those.

 

Thanks guys I'll let him know.