that_guy, yeah you aren't kidding! But mine once it hits half a tank, it just seems to go down, and never stop lol! Think it is trying to win an Olympic Gold Medal for diving!

@shrp, I want the link as well, I want to start keeping track of this truck since I just got it.

@laz, I am lucky the P/O of my tuck didn't have a better mechanic too! Otherwise I wouldn't have gotten it for $1500. They thought something was wrong with the fuel system! Ends up it was the TPS. LOL, I know the feeling!

 

@Jason, ok,air filter and plugs...running ok and not lugging.You'de feel it if it had an exhaust restriction,most likely anyway...like the guys suggested,run through all tune-up related parts and double check.Also look through all your vacuum hoses and connections,make sure it isn't sucking air someplace.check the all the connections related to the plug change also....once again,you'de probably feel it,but check and make sure everything was put back together correct...Then tps and aic connections....
When you did the plugs did you get the ones the guys here suggest? The regular Champions? Also,you looked at them,and I'll get corrected if I'm wrong,but that doesn't mean they're firing with all they can/should be....but I just don't see how one can of seafoam in a full tank of gas should take them out,but they COULD be weakened....Where you're saying it runs good I'm wondering if it's going to correct itself.Maybe the emissions system adjusted with the seafoam in the fuel and now that it's out maybe it'll go back to normal?
@Turbo, probably the only time we'll ever say we like a crappy mechanic eh?...Mine was advertized as "Needs to be towed"..should'a seen their faces when I drove away with it..(heehee) Back to Jason's running issue tho...

 

Good Idea laz, Reset your PCM maybe so the fuel/air ratio goes back to what it was BEFORE the seafoam? Sounds like a good idea!

 

Yeah, missed that....a reset is where it should all start....

 

lol..yeah...Disconnect your negative battery cable and turn the key to the on position for 30 seconds, then turn it off. Reconnect the battery cable, start the truck and let it run for 30 seconds without touching the gas. Turn it off, 5 minutes later turn th etruck on and go for a drive around the block!

I like that spread sheet btw shrp, pretty badazz!

 

I would replace the pre-CAT O2 sensor with a Desno or NTK sensor. Then reset the PCM and see how she runs.

 

ill try the reset and run another tank and see if that does any good. Im not htinking the plugs are weak cause it is running better than before. Has more get up and go. I sell the denso O2 sensors so i can get them for cheep that will be my next step. All i know is the amount my wife drives it to work and home i cant afford $150 a week on gas for very much longer.

 

Take a close look at your front tires, suspension, and alignment as well. My mileage took a *serious* nose dive, coincidentally my front tires were wearing bad. After going through the suspension I found upper ball joints that were pretty worn, replaced the uppers & lowers, had it aligned, and put on a set of Michelin LTX's all around. Mileage is back to ~18mpg consistently (calculated from mileage / gas purchased).

FWIW, my console mpg's show 17.9 pretty religiously as well. My gas gauge also dumps quickly when it gets below half.

Exhaust leaks can also play havoc with mileage.

Bob