Back fire through the throttle body - 1990 Isuzu Trooper

If your backfiring through your throttle body I suggest you recheck your timing and firing order ring

You may have a valve sticking. Just a guess.

Check to see if your timing is off.

May be valve adjustment? lean? Is it rhythmic or random? If its rhythmic find out which cylinder has the problem disconnect each spark plug until the back firing stops.

The throttle body needs to be cleaned, When you disconnected the battery, the computer reset to factory defaults and now with a dirty throttle body, it will run poorly at idle. Make sure both the front side and rear side of the throttle body are cleaned thoroughly.

your timeng is off this can only be reset by a computer as the computer controls is and from time to time thay do go off.

This is only a suggestion but I had a similar problem. I have a 1987 Camaro Iroc z fuel injected. I had a similar problem with the car back firing through the throttle body. It turns out it was the TPI sensor mounted on the front of the throttle body. The sensor is mounted on the front of the throttle body to the left on my car, the opposite side of the linkage. Its black in color and has a electrical connection to the back side of it. Its triangular in shape and mounted with to hex head screws if this is of any help to you locating it. Try adjusting it first that may correct your backfiring problem like it did for me. If this was any help to you leave me some feed back.

153624 firing order ,but i would beed to know about engine build to help more ,like is it fuel injection or carb,diastribtor or coil pack

Check the timing chain..Take the belt of and turn the crank by hand and see how much slop there is when you turn it back and forth..If theres not much then there could be a cam problem.But most of the time its the timing chain..Hope this helps you and have a great night....

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_a3369546f8067589

Chk. your egr valve, that it is not sticking and you got vacume to it. could be carboned up and is not working.