gas mileage dropping-help??

[beige97camry]

97 camry with new motor, valve job etc. was running fine, still is, but mileage has dropped from upper 20s to low 20s with no change in driving habits and over same roads. My thought are clogged fuel filter or maybe vac leak even though idles fine, sometimes it is little high but settles back to normal. tune up was 30k ago. this lack of milelage happened in last couple weeks. motor has 1500 on rebuild. thanks.

[chronoti]

old oil? is it cold enough for winterized fuel? 30k? check air filter, if it has cheap plugs check those too same with the wires. cap and rotor too if equiped.

[Mike Gerber]

Several things can cause this including colder weather. Did you have this car last Winter and were you getting mileage in the upper 20's then? If so, I would start by checking for OBD2 codes. If none are found, I would next check the ignition timing. It might not have been set properly by whoever did the motor rebuild/valve job. If that checks out ok, I would then check the coolant temperature sensor (Toyota refers to this as the ECT sensor in their manuals) for being out of range. It may be telling the computer the car is always cold, when it is actually warm. That would result in a richer than optimal fuel mixture when warm and decreased fuel economy. You will need a DVM and the specs from any manual to do this. If that checks out I would change the thermostat. It may be stuck in the open position causing delayed warmup, if the car actually ever fully reaches normal operating temperature. This too would result in a richer than normal mixture and decreased fuel economy. What does the gage on the dash indicate? When warm the needle should be just below or at the halfway point. The next most obvious thing to check would be for any brake drag. Jack up each wheel and see if the wheel rotates freely with all brakes off. I would start by checking these items and then report back here.

Mike

[bigdaddymak20]

97 camry doesnt have a distributor. Cant adjust the timing. Have you change the oil since the rebuild? Oil could be filled with stuff from the rebuild and fuel filter should have been change at rebuild time, if not change it too. I know its dusty out in west texas check the air filter.

[Mike Gerber]

"97 camry doesnt have a distributor. Cant adjust the timing."

Sorry, bigdaddymak20 is correct. I was thinking about the 5SFE engine in my 94, which still has a distributor.

Mike

[Cambo98]

thank goodness i looked at this post mike you helped me i was having the same problem my brakes are dragging and need a alignment hopefully it well be good this week

[Mike Gerber]

Originally Posted by Cambo98

thank goodness i looked at this post mike you helped me i was having the same problem my brakes are dragging and need a alignment hopefully it well be good this week

Glad I could help.

Mike