1988pathfinderoffroad

I just used an exhaust gas analyzer. I was thining right the first time when my exhaust got hot. Turning out richens the mixture. I verified this, turning in /clockwise leans it out. I set my screw about 1 to 1 1/2 turns out from fully turned in, which is about correct, It's gonna run rich at idle no matter what, but it runs leaner this way and O2 sensor is much more responsive at higher RPM's. Haven't tried it out yet on interstate, but you might want to crank yours in to where I have mine. You can verify the output of the O2 sensor in mode 2 to fine tune it. I bet your gas mileage will improve.

The engine uses the oxygen sensor at cruising speed once the idle/switch is off and the engine is at normal operating temperature and the oxygen sensor is warmed up. You can veryify this easily by probing the O2 sensor signal voltage or putting your ECU in diagnostic mode 2, putting your passenger seat forward and having someone ride around with you in the backseat while they watch the LED's You will see them flash once the idle switch is off and they will notice more blinking at cruising speeds, the truck will go into open loop, if the mixture gets too rich

I definitley noticed more top end power and that is probably where you would see it. I doubt you'd notice any power at mid or low RPM's. The Oxygen sensor would normally take control of the mixture, but accelerating and higher RPMS the oxygen sensor does not function, it would rely on base mixture settings. My truck never cruised at 75 like it did before the mixture adjustment. So the only place you would see benefits from the base mixture adjusment would be under heavy loads and at idle.

Thats what I'm thinking also. I guess floorboard was just getting hot because it wasn't used to cruising at 75 on interstate. When I adjusted mine out it didn't smell as bad either. So I guess it wasn't just my imagination, because it definitely seemed to cruise on the Interstate alot better.

Tungsten, Does it say which way leans/richens the mixture. Sorry I don't have the Haynes Manual.

If I'm not mistaken the person who told me about this screw said it might be covered by a factory plug.

If it is a mixture adjustment. I think turning it out richens the mixture. I took truck on interstate this morning was cruising easy at 75, but noticed the drivers side floorboard alittle warm. I'm thinking richer mixture and exhaust gets hotter. I know the exhaust pipe runs right under driver floorboard.

I had it turned in about 3 turns, which is about halfway, then i turned in out about 1 1/2 turns, so its about 1 1/2 turns from flush with outside of housing. I did notice smoother preformance at higher rpms and truck seemed to gain alittle power. It could be my imagination though. Wish I had an exhaust gas analyzer to test at idle.

I beleive I was told before about this screw being some sort of mixture adjustment but I am not sure. I would like to know what it is though. If somebody else is able to locate it maybe they could tell me the number of turns in I should be at.

Say you're stuck going up a hill, while you're wheelin. Left foot on the brake, right foot on the gas, gear in 1st, click the interlock switch with the ignition on and start the truck while you're giving it gas and feathering the brake. That will keep you from rolling backward anymore.When the truck starts let off brake of course. Just gives you more control because it frees up your left foot from being on the clutch. Main thing is it gives you the option to keep that foot on the brake.

Yeah, I actually saw your post before I found this site. Didn't see it in there, but great post. I'll try to get a pic tonight and post it. Thanks.

I found a small screw at the base of the throttle body on the driver's side toward the rear. Was wondering what this is for? Thanks in advance.