GX - 1st Gen (2004-2009) Discussion topics related to the 2003 -2009 GX470 models

Super bad Mpgs on my 04 gx

Old 05-16-19, 04:07 PM
Join Date: Mar 2019
Location: Louisiana
Posts: 196
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Originally Posted by jprlexusgx View Post
have you tried using seafoam to clean the internals? Also, try a full can on a 3/4 tank.

I know you mentioned cleaning the MAFS but I would suggest buying a new one. It happened to me when I had the FJ that the MAFS was halfway bad and miles started to plunge before I finally got a check engine light. Bought a new one, disconnected the battery for 30 min and miles went back up.

I agree with this.

Do do you have access to an OBD2 scanner that can read pid data?
you should be seeing about 3grams of air per second at idle.

Its hard to diagnose this concern without seeing some mvb’s or pid data. The scanner needs to read live stream data and not just freeze frame data that is stored with codes.

If you don’t have access to a scanner, pull a spark plug out and take a picture of the tip and post it here.
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