Are you sure your 99 has 4 o2 sensors?
I thought only 97 and 98 had that setup? But remember my 05 engine is even wired for 4 even though only 3 were hooked up by Mazda? So odd
The trans is ????? 02+ that’s all I know because it has the second speed sensor
It came from junk yard, it actually originally was in this truck… and now they are back together
I installed the pcm, key and tumbler as well as pats module yesterday… took the truck for a loooooong test drive. It’s running and shifting properly for the FIRST TIME since I built it!!! Finally!!
I have one code still… canister purge circuit control failure… it dawned on me I have seen this before. Can’t use a ranger canister purge valve with an explorer pcm. So I need to swap to a 99 explorer canister purge and then I expect no codes!!!!
I am going back to the junk yard next week this key and pcm came from I want the front door locks so I can make this ranger use one key
I’m very happy!!! Finally!!!!
Some sohcs had 4 ea 02 sensors… when the exhaust stays in two pipes leading into the muffler you have 4, on most sohcs after 99??? They went into a single pipe after the y pipe and they only had 3 sensors. Maybe 99 was the crossover year? I dunno
I do know that so far this thing is happy and the trans shifts great! Engine runs awesome.
It’s been a looooong battle on this build. I learned a lot
Persistence is the word of the day
Next I’m going to finally put in the manual tensioners and then we can think about a paint job

green Monstaliner