Blimey Cooperman I think you over estimate my ability, my background is electronics. Truth is what I know about internal combustion engines you could write on a fag packet and still have room for the lords prayer!!

Richard one other thought I am sure you are aware that when a fault code is generated the OBD system takes a snap shot of various parameters called a freeze frame. If the problem reoccurs this may be worth a look at if you haven't already.

Here is an example. With my misfire problem, a short blip, about once or twice in a 50 mile trip, that occurred when accelerating or maintaining a constant speed uphill, ie when the engine is under load, the freeze frame data was as follows

Freeze frame DTCfrfz P0301
Fuel sys 1 ol-drive
Fuel sys 2 n/a
load_pct (%) 97.3
ect (deg c ) 86
shrtfti (%) 0
longfti (%) -0.8
map (kpa) 99
rpm 3335
vss km/h 46

You can see from the above that the problem occurred when the engine load was at 97.3% confirming what I already knew by observation but putting a figure to it. The fuel system was in open loop ie disregarding the O2 sensor which according to the internet is what it should do when accelerating. The engine coolant temp was 86 deg. The short term fuel trim, that is the difference between the long term fuel trim and what the PCM was providing at the time was 0%. The long term fuel trim that is the difference between the standard fuel requirement for these conditions and what the PCM has chosen over a long period was -0.8%. The manifold absolute pressure was 99 kpa. The rpm was 3335 and the speed was 46 kph.

Some of this stuff might be useful in getting to the bottom of your problem.


Regards Tony