gas mileage gone to hell

[redlineracer]

can someone please help me here i got my 240 3 weeks ago and last week the gas milage started going down like 8 mpg i cleaned out the throttle body did a basic tuneup used synthetic oil but it dosnt seem to help...its not a fuel leak and it dosnt bog out when i drive im not sure what it is

[480sx]

Could be your O2 sensor, or your maf, if you already did a tuneup(cap, rotor, wires and plugs) those are the next 2 things to check.

[s14_240sx]

you sure its not a leak? My car just started leaking, and my milage went from good to **** in like one day. Get under your car and check to see if theres any gas on the parts.

[Rufiotwin]

Same thing is happening to me. If it's a 1995+ model I think, go to Autozone and they'll do a free ECU scan. Otherwise I hear they sell code scanners for like $50. Other thing you can do is what I'm doing, get an Ohmmeter (what like $30?) and check your MAF, Throttle Position Sensor, pretty much anything you can hook it up to... also replace your engine coolant temperature sensors and your o2 sensor. Don't know anything else on the top of my head. Anyone else got any ideas?

[aceof07]

dude i got the same problem. what i've heard of so far is fpr, injector leak, maf, o2, tps, coolant temp sensor, maybe a vacuum leak. let us know if u have any luck!

[2.4Loflove]

might want to check out your knock sensor too.

[ricebike]

y not run a trouble code scan??? http://www.240sx.org faqs section...

[aceof07]

try to reground ur maf, it does wonders!