charcole67

So I just bought a 95 4runner 5 speed with the 3.0 It's my first toyota and my first vehicle with fuel injection, frankly the newest car I've owned but it's time for a reliable truck. I'm a chevy guy at heart and have no problems workin on old cars or motors. But with all the junk on these newer motors I'm a bit lost.

The body has 190,000 miles on it but the motor was replaced 40,000 miles ago. It runs great except when it's warm the idle likes to drop. It runs and drives fine but when I come to a stop the idle drops and fluctuates between 300-500 rpms for a few seconds then levels back out around 800 rpms. If I rev the motor a bit before I completely stop the idle won't drop and stays at about 800 rpms. My guess is a dirty EGR valve or dirty throttle body?! If anyone has had a specific problem with this I need some help. I'd like to narrow it down before I start takin things apart or spending money. The plugs, wires, rotor were all replaced with new engine. Vacuum lines are fine. When I first start it up in the morning it's fine but once it gets to temperature it will drop when I come to a stop.

Any ideas?!

dropped_dime98

check of codes. My 91 with the 3.0 ran around 400rpm and all i did was swap in some new plugs and wires.

Noltz

Welcome to YotaTech!
Sounds like a dirty idle air solenoid, or a Throttle Position Sensor out of adjustment.

Easy enough for check for the first one; Take off your intake tube from the air filter, and use a little Throttle Body Cleaner (just like Carb Cleaner), and clean it like you would the idle circuit of a carb Just a little above idle, squirt & recover.

The second is fairly easy to check; Unplug your throttle position sensor. It's on the throttle body, opposite of the cable cam that opens the butterfly. Just unplug it and start the truck. The Check Engine light may come on - that's normal cuz it can't "see" the sensor. If the truck runs better, you've got a bad / out-of-adjustment TPS.

abecedarian

if the egr valve is slow to close, that could cause the problem you're describing
throttle dashpot and/or air flow meter could cause a problem such as this too- throttle closes too quickly, afm closes fully (due to inertia in the vane) and has trouble re-opening to the proper angle.

whichever way, by opening the throttle a bit during decel, you're allowing whatever is the problem to return to 'normal' condition and clear the issue.

charcole67

I appreciate the info. I'm goin to check it out tomorrow and see if I can't get it figured out. Thanks

charcole67

------Sounds like a dirty idle air solenoid, or a Throttle Position Sensor out of adjustment.

if the egr valve is slow to close, that could cause the problem you're describing
throttle dashpot and/or air flow meter could cause a problem such as this too- throttle closes too quickly, afm closes fully (due to inertia in the vane) and has trouble re-opening to the proper angle.------



So I checked everything out. Dashpot and VCV are good. TPS is good. Ran some troubleshooting and decided it's the air valve. According to what I read to test that when I turn the idle screw in all the way when the engine is cold it's supposed to lose rpms but if I turn it in all the way when it's warm the idle shouldn't move. Well when I started turning the idle screw with the motor warm it immediately started to lose rpms. So according to the repair manual I have a bad air valve.

The only problem I have is that I can't find it. The manual does not say where it is. There is a picture but see nothing like it. If anyone might know where the air valve is that would be awesome. I have a feeling it's goin to be on the back side of the motor along the firewall...the only place I can't see. I did adjust the idle and it helped my problem a little bit. It still lost rpms comin to a stop but only got down to about 600. As of now that's good enough for me. Thanks for all the suggestions.