This time last year I was having major issues with an ECM connector that had been mangled, first by techs piercing the wires right next to the connector, and later by me, drilling out the back of the connector and sticking the broken/corroded wire through it, and reseating the connector.
I went and got another connector from a junkyard, and got myself a can of CRC QED cleaner to flush out the old dielectric grease and clean up the connectors.
Somebody told me I need to get some DeOxit, but I foolishly resisted this product recommendation and declared the connector pristine, after using the CRC QED cleaner on it.
My ECM connector issues persisted, they were ultimately broken solder joints on the connector pins which I resoldered, but before this, I got the Caig Deoxit industrial survival Kit sold on Amazon, and got it into the "pristine" sockets in the junkyard connector, and used some precision swabs inside the sockets.
They got shredded as if I was trying to polish 220 grit sandpaper with a tiny Q-tip, and turned black. More deoxit, more swabs until the insides of the sockets gleamed like oiled chrome and the swabs came out pink with Deoxit and showing no signs of abuse.
These contact surfaces oxidized so badly, despite being immersed in Dielectric grease their whole lives.
Later on I Went a bit Nutty with ALL my sensor connections, and all my electrical connectors everywhere.
The TPS, Map and 02 sensors connectors were particularly bad.
Afterwards, it felt like the vehicle dropped 500 Lbs, and some MPG I thought lost forever due to larger and heavier tires, returned. I passed a Smog test with my best numbers ever, and the ONLY thing I did since the last smog test 2 years earlier, was clean the all the sensor and ECM connectors with DeOxit.
I now use Caig Deoxit Gold g5 or Shield for the long term protection of conductive surfaces, after cleaning with d5 spray or d100 liquid.
After the connector is reseated, I try and mush in as much Dielectric grease as I can to prevent water and air intrusion around all possible entry points of the connector.
All the connectors I pulled apart and which were extremely oxidized, had been smothered in Dielectric grease and the oxidation formed anyway.
I consider the Caig products to be near magical electrical juice.
Try some on your Phone's charging and data connector. It is a lubricant too.
I basically never undo any connector without giving it a blast of some Deoxit d5 spray and giving it some time to work, and swabbing out the extra. The swabs rarely come out unscathed, even from connectors which appear 'just fine', even to the aided eye.
These Swabs are tightly wound and tiny, about 1/10 the size of a normal Q tip:
http://www.amazon.com/Tamiya-Cotton-Tria...on+Swabs+tamiya
These mini bottle brushes can be picked up in the dental section of your local pharmacy:
http://www.amazon.com/Dentek-Slim-Brush-...ntek+slim+brush
These can get inside sockets on even smaller connectors to abrade any oxidation and help the Deoxit do its job.
My glass fuse panel clasping arms were also in horrible condition. Deoxit d100 alone did little on these, but wrapping some q tip heads with 1000 grit sandpaper and wetting the Qtip with DeOxit turned white oxidized metal into gleaming chrome with some finger work, and solved some intermittent issues I was having with power windows and door locks, and brake lights.
I bought some of their Faderlube, for potentiometers. The cheap 10 turn potentiometer I added to my Adjustable voltage power supply had developed some wackyness which the F5 fader lube solved, and now I can dial in voltages to 0.01 of a volt easily and smoothly.
Be sure to protect your skin from these products. They won;t burn you, but skin presents little to no barrier from their active ingredients.