I just bought a 05 ram hemi 2 months ago and I started out getting 13.5 mpg and now recently I'm only getting 8.5 in town and Idk why. It's bone stock and I baby the **** out it. Any suggestions?

 

Well you bought it used so more than likely you have no idea what anything looks like internaly, and you probably dont know when the last time Mant was done and how much was done.


When buying a used Truck its much better to just change out what you know breaks first and what you would usually do in a 100k tune up even if the Truck isnt a 100k.
Sometimes it can get expensive even if you do all the work yourself so just start out easy Get Plugs(Your Truck Only likes Copper plugs just remember that) change the oil, Do you have any Trouble Codes?Any noises? Alll the tires around the same pressure? Changing your o2s could help but wouldnt recommend replacing them unless you have the tool.

BTW 9 is pretty average

 

change all 16 of the spark plugs & wires... I am betting you are getting a bad burn.

Don't touch the O2 Sensors until you've verified the plugs are fine.

Once you get the plugs and wires done come let us know whats up.

 

Yeah after i wrote my post i thouht dang i hope the OP dosent change the o2s first with out atleast changing the plugs. That would be a waste of money and he would have to buy o2s twice.

 

Always change the plugs and air filter when buying a used car. Even if they say they just changed them.

 

How does the average joe assess the situation/need to change plug wires?

 

Check wire end to end with an ohm meter, of course, one at a time, make a note of each wire reading and the ones that are not in line with the average are suspect

 

Gertie240 hit the nail on the head... that's exactly how you check them.

The service manual should tell you what the wires resistance range should be, but if one is way far away from the others it is likely bad... and when I change one of them I change them all.

 

I agree with the plugs and wires..just so u kno the back 2room cylion the drivet side are a little tricky..and 9mpgu isnt right..i have an 06 hemi regular cab and i can get 15 in town when the mds is turned off

 

Im assuming you were trying to say that the back 4 plugs (last 2 Cylinders) are tricky to get to?