possessed 3.4

[birdman]

Over the last mabey 6-7mo or so the lumina has been acting very.... moody. it started with the engine light and brake light coming on(ran fine). if i turned it off and restarted it, gone... and sometimes it would be fine from the get go. other times it would start and act like its running on 4 cyl, but if i truned it off and restarted it it was fine. another favorite of the lumina was to run fine but as i would come to a stop the idle would dip down around 400 unless i stopped really slowly. well about a mounth ago i started it up and the idle went from about 1k and gradually made its way up to 2k. so i shut it off and restarted it and again it started at 1k and proceeded to climb, well that time before it got too high i poped it into gear, sat there for a sec and thought ill just make it home and mess with it there, as soon as i got rolling(1-2mph) the idle dropped down to normal and ran better than it has ever run. i also noticed that while i was driving it seemed like it held gear longer than normal. that went on for about a month until now, ill start it up and it'll run ok but when i put it in drive the idle seems a tad low and when i come to a stop it drops down in the 400 range and kinda bounces, im personally clueless to what the hell is going on with this thing the only thing i can even imagine it may be is the ECM. any help would be great.

[MonteCarloDude]

L67 swap?

[jeremy]

I doubt that it would solve anything, but have you tried doing an idle relearn yet?

[jeremy]

...oh yeah, what codes from the Check Engine light?

[19Cutlass94]

Please tell me you found out what codes the PCM threw.

[birdman]

yea ive done the idle relearn countless times and the last few times i checked the ses codes they alaways semed random but ill check again.

 

EDIT: just checked and the codes it has are 42 and 51.

[White93z34]

CODE 51

 

Trouble Code 51 indicates that the ECM sensed a fault in the MEM-CAL. On power-up, the ECM does a checksum of the MEM-CAL to ensure the MEM-CAL integrity is good. If the calculated sum does not match the sum in the MEM-CAL, the ECM will hardcode 51 and enter Back-Up mode, since the ECM cannot know where in the MEM-CAL the fault lies.

 

Code 51 is set when:

 

the actual MEM-CAL checksum does not match the value in the MEM-CAL

Possible causes include:

Incorrectly installed MEM-CAL module

Defective MEM-CAL module

Defective ECM

 

Edit: I am 90% sure I have at least 2 spare 3.4/auto ECMs one I believe is from a 92' we well PM me if you are intrested

 

[GOT2B GM]

is the aux power terminal nut tight?