Assuming your 1995 Isuzu Trooper is using the 3.2 SOHC engine, the firing sequence would be as shown here. . This was originally posted here. An actual image which was originally posted here.
Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.
Ya sounds like the electric shift solenoid. Problem with electrical. Will not give you a warning. Will go bad in a heartbeat. You can try unhooking plug that gos into the trans and spray electrical cleaner on it. plug back in. Wiggle some wires and maybe find one loose or broken wire or connection and hope for the best. But its probably the tranny with that many miles. Go to Advance Auto Parts they usually scan your car for free for codes. Good luck
Isuzu doesn't publish there owners manuals to the free Internet, you must buy the manual and it contains the diagrams you need. You can buy a used one HERE That is the owners manuals for all 1995 models.
does the speed change at all? does the speedometer if you noticed is working? if the speedo is not working then the problem is your speed sensor on the gear box is not working and that is the reason the automatic transmission stayed on safe mode. renew the speedo and will work ok.
. This was originally posted here. An actual image 
which was originally posted here.
