I have a 1997 sl1.. It drives great ive had since the beginning of ''08. through out the summer and the fall it got pretty good gas mileage (about 24-26 mpg city and 30-35 highway). I dont drive crazy and dog on it. I drive it fine. But since about october its been getting bad gas mileage.. like 18-20 mpg. But its been getting worse as time goes by.. now its getting like 15-17![img]smileys/smiley7.gif[/img]. I have no idea whats wrong. It drives fine. Nice and smooth. Nothing has changed as far as how it sounds, drives or feels. I dont know whats wrong. I replaced the plugs, wires, air filter, i ran gas treatment through it, ran it with premium fuel, and ive even changed the oil and everything[img]smileys/smiley11.gif[/img]. I dont know what to do... SOMEONE HELP!!!

 

I heard a bad EGR valve will cause bad gas milage, is you service engine soon light coming on?

 

Most common thing to check first would be the coolant temperature sensor and/or its electrical connector. A bad one would greatly decrease gas mileage.

 

i got the new sensor.. now how do i install it?

 

Did you get the connector?

 

I dont know if he did, but I grabbed 35 of them a week ago at the junkyard.

 

no.. all i got was the sensor