TOPIC: 1990 Mitsubishi Montero, 3L, Costa Rica

Hi Jonathan,

Sounds like you can do all that by opening the throttle plate a little.

Keep in mind, the more air that passes over the groove, the better the response.

Looks like an adjustment to bring it up around 400-500rpm when cold would put it around 700 give or take when it is warm.

Karl Fortner
Tacoma, Washington

Thanks Karl,

I got it done. When we did the test drive with a lower idle, there was a bit of a jerk or clunk when he shifted in lower gears, this went away with the slightly higher idle. I have no idea what that was about. I was also surprised that his brakes are working much better after the mod. I guess the increased vacuum is helping the brake booster.

I did a vacuum check on a few lines. The Evap. Emissions purge line and the fuel pressure regulator (I think that's what it was) both showed 22", but the brake booster only got to 21". Is 1 inch of mercury anything to be concerned about in terms of vacuum leaks? It stays steady at 21".

Just to share the results. Mileage on this one is about 15-25% better now. I'll regap the spark plugs next and see if that makes any difference.