Note, this vehicle is currently driven very little, mostly because of this issue -- less than 3k mi in the 15mos, and maybe only 500mi since Halloween 2016.
HELP! I've fighting this 2003 Liberty 3.7 gas with ~150k miles now for the better part of a 9 mos, both myself and with the help of two shops, and so far no lasting progress. Basically each time we make a fix, the misfires comeback within at most a couple weeks. There have been no codes observed other than misfires. We live at 7800ft altitude, with a 1800ft elevation interstate drive from town. Between replacing the plugs and coils, and the MAP, I barely made it home one day because the engine was running so roughly and wouldn't accelerate past 35mph. After the MAP, it ran beautifully for 1 month, then back to general roughness esp at idle, misfire codes
What else am I looking for here? This is driving us batty! One other shop suggested a full head-gasket both sides with machining which is $2k+, but with no apparent compression problems that seems wrong. Another shop suggested maybe a plugged CAT causing back pressure ... does this even make sense in modern CATs (I thought this was an 80's and 90's problem that rarely exists today).
What has been done:
- compression test - all cylinders similar and OK
- all new plugs, factory OEM, gapped
- all new ignition coils
- new MAP sensor
- new muffler (not related, but fyi)
From my ODB2 scanner (these are the only ones I recorded), there were more instances
Nov 02 2016 - P0300, P0303, P0305
Dec 09 2016 - P0300, P0302, P0303
Jan 14 2017 - P0300, P0301, P0302, P0303, P0305
HELP! I've fighting this 2003 Liberty 3.7 gas with ~150k miles now for the better part of a 9 mos, both myself and with the help of two shops, and so far no lasting progress. Basically each time we make a fix, the misfires comeback within at most a couple weeks. There have been no codes observed other than misfires. We live at 7800ft altitude, with a 1800ft elevation interstate drive from town. Between replacing the plugs and coils, and the MAP, I barely made it home one day because the engine was running so roughly and wouldn't accelerate past 35mph. After the MAP, it ran beautifully for 1 month, then back to general roughness esp at idle, misfire codes
What else am I looking for here? This is driving us batty! One other shop suggested a full head-gasket both sides with machining which is $2k+, but with no apparent compression problems that seems wrong. Another shop suggested maybe a plugged CAT causing back pressure ... does this even make sense in modern CATs (I thought this was an 80's and 90's problem that rarely exists today).
What has been done:
- compression test - all cylinders similar and OK
- all new plugs, factory OEM, gapped
- all new ignition coils
- new MAP sensor
- new muffler (not related, but fyi)
From my ODB2 scanner (these are the only ones I recorded), there were more instances
Nov 02 2016 - P0300, P0303, P0305
Dec 09 2016 - P0300, P0302, P0303
Jan 14 2017 - P0300, P0301, P0302, P0303, P0305