5th Gear Member
Join Date: May 2008
Location: San Francisco, CA
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uggh!... fuel trim problems... i hate these :-(
what it is fellas is that the brain cannot adjust the variables to achieve the 14.7:1 air to fuel ratio +/- a tolerable percentage. Several factors come into play here, unfortunately.
First, when was last tune-up? compression check, plug change(are they the correct range?), and air filter and don't forget the secondary air pump filter also. If these have not been serviced within any recent time, i suggest u do your basic tuneup first before you dig deeper. And don't forget to check for vacuum leaks.
Second, the sensors... AFM, TPS, 02 sensors. But let's not go into this for now.
Do the tuneup first so we eliminate the mechanical probs before u start probing the electrics.
* i almost want to suggest to go for a smog check- the readings for HC, CO, and NoX will surely provide a clue as to what could be wrong.
* when you take out the plugs, let me know the color of the electrodes.
Last edited by darkhorse737; 07-16-2008 at 11:57 PM.