Ford Ranger 1998 Ford Ranger Xlt Drive Cycle

You have a mis fire on cylinder 2 still. The p1507 may be several things, the simplist to do is to pull the IAC motor off and clean it with intake cleaner. While your at it, access the throttle body and clean the plate, may want to use a brush as well in conjuction with the intake cleaner. While this may not solve it, it is where I would start.

This is the right place to post.

Not sure on the IAC, maybe someone else can chime in.

I get nervous about what goop you would use. If it isn't O2 sensor friendly or temperature rated, it "MAy" cause problems.

One of the other moderators heavily stressed to not use intake cleaner on the throttle bore as I do.

P1506 Idle Air Control Over Speed Error
Replace the IAC Especially since you poked a hole thru something. The P0302 is #2 cyl misfire. Is the motor skipping a bit? Check and see if you fouled the new plug. If so Do a compression test.

Are there any codes present? If you have access to a good reader hook it up and check the emmision system inspection readiness This will tell you of possible codes before the light comes on!