Need help on VERY poor gas mileage!
Registered User
Joined: Sep 2009
Posts: 17
Likes: 0
From: San Jose,CA
James, I have 2003 GCV 3.8L , I bought it used back in July-2009 , the city milage was 10-11 mpg, I asked lots of questions in several forums to find the way to fix it, but still problem.
As a player I replaced lots of part ( sparkplugs and wires, air filter, fuel filter, both oxygen sensors, map sensor, air temp sensor, coolant sensor, themostat) but only gain from 11mpg to 12mpg.
In May-2010 I had a trip to San Diego from San Jose, I noticed on high way milage I got 20 mpg. When I was in San Diego I talk to some friends about my van MPG, a friend of mine took me to a "work at home mechanic" and the mechanic told me that the PCM needs to be reprogramed. "Why ?, nothing's wrong with PCM", I asked the mechanic, "believe me" he replied "I charge you $130.00 that's not even half of the money you spent on parts you replaced".
Well, I told my self this is the last time I put money on the van, if it's not fixed I'm gonna sell it away, finally I let the mechanic reprogram the PCM.
The next day I filled the van up and drove back to San Jose, on the road I notice the MPG increased from 20MPG to 21MPG that surprised me.
When I get home I filled the van up and recorded the MPG to see if it would gain any, after this I found out the city milage is 14MPG, now sometimes I can get up to 15MPG if I take it realy easy, but I don't think I can get up 17MPG as claimed.
Wish you luck with the van.
As a player I replaced lots of part ( sparkplugs and wires, air filter, fuel filter, both oxygen sensors, map sensor, air temp sensor, coolant sensor, themostat) but only gain from 11mpg to 12mpg.
In May-2010 I had a trip to San Diego from San Jose, I noticed on high way milage I got 20 mpg. When I was in San Diego I talk to some friends about my van MPG, a friend of mine took me to a "work at home mechanic" and the mechanic told me that the PCM needs to be reprogramed. "Why ?, nothing's wrong with PCM", I asked the mechanic, "believe me" he replied "I charge you $130.00 that's not even half of the money you spent on parts you replaced".
Well, I told my self this is the last time I put money on the van, if it's not fixed I'm gonna sell it away, finally I let the mechanic reprogram the PCM.
The next day I filled the van up and drove back to San Jose, on the road I notice the MPG increased from 20MPG to 21MPG that surprised me.
When I get home I filled the van up and recorded the MPG to see if it would gain any, after this I found out the city milage is 14MPG, now sometimes I can get up to 15MPG if I take it realy easy, but I don't think I can get up 17MPG as claimed.
Wish you luck with the van.