93 ATX poor mileage in town

[etcsho]

My 93 ATX gets terrible mileage in town (10 - 12 MPG), but does great on the interstate (22 - 24). Any thoughts on what I should check. It has 125k miles on it, and has had two 60K services (the last around 110k).

 

[SHOfun 93]

maybe you need to replace your catalytic converters causing your motor to run rich off of stops. I dunno.. shrug

 

[etcsho]

I had new cats, along with a Doug Lewis ATX, installed last summer at FPS in Atlanta. The mileage has been this way for the last few months.

 

[SHOfun 93]

Well then you have your drivetrain problems solved for a LONG time...but back to the fuel problem. Has it thrown any CE light codes at you? It might be a bad MAF sensor or some other sensor relating to A/F. There are soo many of them.

 

[svtman]

Yeah - I'd say check your codes and make sure you are running premium. My 95 ATX just went on its first highway trip and I got 34MPG (Imperial) doing 110kmph. That was with a bad 02 sensor and slight misfire. I figure I will get 35MPG once the rest is fixed. Too soon to tell what city mileage is as I have not had it long enough and am driving it too hard!

Dave

 

[NotSoSlowSHO]

I hate to pull out the bs flag but there is no way you could get 34 MPG in ANY SHO with bad O2's. Especially an ATX.

Also, gas mileage and PREMIUM gasoline have very little in common. It has been proven time and time again that the SHO does not need PREMIUM. And with an SHO motor that is already in need of attention, premium gas might do more harm than anything.

ETCSHO~

Start with diagnistics first. Pull some codes and go from there. There is obviousy something very wrong with your engine.

 

[svtman]

You're right - the mileage could have been out as it was a relatively short highway trip. My figures being used were 15L of fuel for 185km which works out to 34mpg. Time will tell if it is accurate now that I have new plugs, wires, and fixed my 02 sensor...

Dave