Hey there guys well this issue has recently started, it is not consistent but it worries me, my 85 TA has a 700R4 and 63 xxx miles, I have noticed this problem occurs in 2 different situations, the first time it started after driving normally then I punched it down a random road and around 2750k-3k RPM it made a grinding stutter sound and it wouldn't shift up at all unless I let off the throttle.. right after that the check engine light came on. If you turn the engine off and on it (check engine light) will go away even in closed loop mode. I drove it a few more times without really flooring it, and no such issues. Except for today when I tried again it happened except this time it did it when I floored it and it downshifted no grinding stutter noise or stall but the check engine light did come on I drove it like that home with the light on and floored it just once more to test for a grinding/stutter noise but nothing. Its very odd and I really don't think it is actually a tranny problem perhaps a speed sensor going out? Maybe even tv cable?? NOTE: I did recently replace my stock AC 02 sensor with a Bosch Premium style 02 sensor, could that be it???

Any input or advice would be greatly appreciated I wanted to check with you guys first before I blow my pockets at a shop.

 

check the coolant temp sensor..near water pump?...