I'm going to look at a '94 Z28 tomorrow but the guy tells me on the phone that he gets like 12-14 mpg with it. He doesn't sound like a car guy and doesn't sound like someone who keeps his foot in it all the time.

Any ideas what I should be looking for when checking it out? Since it seems that most talk 18-20 in town and 24-26 on the highway, this 12-14 mpg is a red flag.

Thanks.

 

Fouled plugs, clogged fuel filter, dirty air filter. It may need O2 sensors replaced.

 

02StanGT pretty much covered it. Spark plugs, wireset, PCV valve, fuel filter, air filter, and O2 sensor.

 

If the O2 sensor is bad, it should show on the engine codes, correct?

How do you read codes in a '94?

 

http://www.obd-codes.com/faq/read-gm...codes-free.php

Read that to learn to read codes. If the O2 sensor is faulted, it will generate a code. If it is fouled, it may or may not generate one.

 

Connect an OBD scanner to the OBD port in the car. Should be below the steering column area.

 

That's the mileage I get around town (I think). Of course I have a heavy foot.

 

I average 16 around town, so it doesn't sound like you're too far off. To put things into perspective, when I had a fouled plug I got about 8-10...

 

I looked at this '94 Z28 today.I tried to get the diagnostic codes but it wouldn't flash anything. Since he said it gets about 12-14 mpg, and the exhaust tips are pretty black inside, I figure that the O2 sensor is shot. But not getting it to give codes bugs me. He says he has had it in for tune ups and the mechanics were unable to rectify the low gas mileage. If it is a sensor, then I would think they could find that and replace it.

The car has a little rust on the core support bar and the headlights. It used to be in Ft. Lauderdale and the guy likes to live and hang at the beach, so I'm assuming this is from the salt spray and salty water on the roads you get there. The rest of the car looks clean enough.

 

Is the "Check Engine" light on? I'm sure the mechanics wouldn't touch the O2 sensors if the light wasn't lit. Did you drive it around?