A decent mechanic should have put the car on the diagnostic computer and narrowed it down by the codes in the car in about 5 minutes.
I'm rather ticked at Pep boys in DC, They can change the oil in a car ok but couldn't locate torn CV boots or leaking struts when the car was in the air during a safety inspection. The mechanics were to busy trying to pick up my daughter and her friend for dates.
The air filter was checked and it was fine :( The trans isn't stuck in a lower gear either. Additionally, It was averaging 23 miles per gallon in the city. It wouldn't just randomly drop to 9 miles per gallon out of nowhere and stay there for the past month.
Did you do city driving? The computer just does an average. I've seen them bounce from 4 mpg to 30mpg.
Take it out for ten miles on the highway if it is still running well and see if your average goes back up.
I wouldn't trust a mechanic that had it for three days.
Add to the list: check for a brake that isn't releasing . . . . only suggest that since the onset was sudden, not gradual.
the compressor would not be related to that. check the air filter and see if it is not dirt. also, if the trans is stuck in a lower gear, mileage will be effected.
Sounds like a fuel system problem, have it analyzed at the dealer.
My car went from 23 miles per gallon to 9 miles per gallon in a day and it hasn't gone back up. I brought it to Pep boys who did a smoke test (among other things) and couldn't find a leak or anything else wrong. I then brought it to a local mechanic who had it for 3 days and checked to see if the compressor was broken and it wasn't. Any suggestions?
