My 85 is getting about 13 highway.... What could be causing that? Should be getting better than 13

 

Spark plugs, driving in a hot day. .. I've had a crappy battery effect my mpg I would assume due to weak energy. How is your alignment and tires. What type of gas do you use.

 

what did it get before?
did it drop suddenly or has been getting worse?
if you have the carb'd 2.8 I wouldn't expect more than 15-16mpg

 

Slightly larger than stock tires. Battery needs replaced soon.
Pretty sure it was tuned up about 800 miles ago. Alignment and tires were done 600 miles ago.
It has the 2.5 amc. It seems like its getting worse and the weather has been high 80's to mid 90's. I'm running 89 in it right now. I drive 52 miles a day. 26 in the morni g and 26 in afternoon. Have the 5 speed and do on average 60-65. Rpm is about 2500-3000.

 

Basic tune-up items, bad 02 sensor, vacuum leak. There can be a lot of reasons.

 

Would it act up in a way if it was o2 sensor? I don't think there are any vacuum leaks.

 

Where is the o2 sensor located?

 

02 sensor is located on the down pipe exhaust.Before the Cat.converter.You can have it tested to see if its bad.Also clean throttle body,clean I.a.t.Clean your battery terminals if there dirty.Get it tested at local auto store to see if there is any codes.They might do it for free not sure..Good luck!!

 

What is I.a.t.? This may be a stupid question but how do you clean the throttle body?

 

85 four cylinder is carbureted...........

See if the carb itself is loose between it's base and main body.

 

Not going to get a lot of codes on an '85 2.5.

 

ohh yeah..I realized it was carb after I posted..You can clean carb with Carb cleaner and you probably don't have I.a.t. sorry..

 

It will run crazy rich. Stomp on it and you'll get black smoke from the exhaust.


Why do you think that? Have you done any testing? Or is it just a 'feeling' you have?

 

Could be the carb needs adjusted or possibly a rebuild. Get it running to operating temp. Try adjusting the carb if there is a way to. Some have the adjustments plugged (we use to drill them out). If there's a way to adjust it but it won't respond it's time for a rebuild. Or with it running and the air filter off look in the carb and see if it's dripping gas at idle. If so it's time for a rebuild.

 

My favorite method of diagnosing involves no hands-on testing.
I much prefer contacting the spirit world. A tried and true method is to get a group of like-minded folks together, hold hands in a circle around the vehicle, and sign Kum-ba-ya.