Cost: Less than $50
Special Items Needed: Can of throttle body cleaner, clean toothbrush
If your engine just doesn’t seem to have the same punch it used to, or your idle is rough, you may just need to clean out your throttle body. I’m not sure what all years/models have throttle bodies, but my 95YJ does.
The throttle body is located at the engine-end of your air intake duct. With your engine off, simply remove the duct from the throttle body. On my YJ, this is done by removing the plastic clamp holding the duct to the throttle body.
Take a can of spray throttle body/carb cleaner (I used Valvoline synth throttle body cleaner) and spray the inside walls of the throttle body. You may need to use the toothbrush to get some of the tough grime. Manually open the valve and clean both sides of the valve, and completely underneath. Get your toothbrush in there too. It may take a few minutes, but you can get the entire TB to like-new condition.
Wait for 10-15 minutes to allow most of the cleaner to evaporate, then start your engine. It may take a little longer than usual (don’t try to long at one time to save your starter and battery). Also, when your engine first starts, it will probably gasp, clunk, and blow all kinds of smoke, but it will clean up.
With the engine revving around 2,000 RPM’s spray short bursts of the cleaner into the intake. BE CAREFUL, THIS COULD POSSIBLY CAUSE A BACKFIRE AND A FLASH BURN. You should wear safety glasses and other necessary safety equipment. I’ve not had anything like this happen, but do be careful.
You’re done! You should add this maintenance to your “scheduled maintenance” list. Cleaning every 12,000 – 15,000 miles is recommended.