My gas mileage dropped from around 30 mpg to an average of 14!!! My exhaust also smells very gassy, even from the cab...

I gave my truck a much needed tuneup which included:

changing oil
new clutch fluid
new brake fluid
coolant flush
new battery
new plugs
new exhaust

This was after my truck had been running one plug short (of the 8) thanks to it breaking off below the hex part. This was fixed by a shop, but would this have ruined something in the week or so it was like that? O2 sensor maybe? Any help would be appreciated!

 

Try running some fuel injector cleaner through it also check the air filter and replace as necesary also change the fuel filter

 

diagnostic on it, this may shed some light on the problem

 

I'm lucky to get 20MPG on the HWY with new plugs and wires guess it's time I get the filter changed and the injectors cleaned.
It's at 79000 miles and I also get no codes from my Actron....

 

Check your coolant and temp. Your temp gauge should read around mid-range. If your thermostat is stuck open, or your thermostat has been replaced with a cooler one, it will make the computer think the engine isn't warmed up and run richer giving you that gas smell. I went from 29 to 19 mpg on that one myself with my truck.

Lastly, your catalytic converter might be cloged, but not as likely as a bad thermostat. A $3 thermostat is a LOT cheaper than a $200 catalytic converter. Good luck!

 

I have a 97 Ranger with the 2.3L I am lucky to get 20mpg on the highway. I changed oil, filter, air filter, spark plugs, wires.

The motor had 111000 miles on it, and still had the original plugs, and wires on it.

This is the motor with 8 plugs

any suggestions

 

I just found that the original owner NEVER changed the PCV valve in 115K miles and it was gummed up horribly.

I also found the whole inside of the intake was covered with black oil, most likely caused by oil mist entering the intake from the bad PCV valve. It crapped up the Air Charge Temp Sensor (intake manifold on cylinder 1 rail). I replaced it and my MPG went up from 19.5 to 23 immediately. I noticed the extra power also.

The only computer code I still have is 41 (the HEGO (O2) sensor) and it won't budge yet. That's the weekend's project!

I'll get to 28 yet!