94toyota4x4

I have a 22re and it seems to act pretty werid sometimes, every once and a while it feels as if its making close to nothing for power, it mainly does that in the morning, I mean it feels like im draging something, I cant even get it passed 50 mph when it decides to do this,what could it be>

all_terrain17

I have the EXACT same issue! Hesitant at times right after start up for 2-3 minutes, other times power is decent yet the motor chatters a lot, and yet some days power is great even from the start.

I have no idea what the problem could be or where to start looking.

Swear the motor seems to have more personality and feelings than a lot of people do...

AH64ID

my runners re did that a few years ago, it was the coolant temp sensor.. There are two i guess, one for the gauge and one for the ECU.

Elton

changed the fuel filter yet ?

Yotapup

Check The ECT sensor and The Cold start injector switch on the front of the intake. Also check the lovely EGR valve.

GrimReaper

On a RE 4x4 there are up to 6 temp sensors.

Two below the water neck are main ECU temp sensor and the cold start timer temp sensor that controls the cold start injector. The cold start and ECU main would be where I would start testing. I think the haynes has the Resistance vs temp listed.

The other three sensors are:

Top of water neck on the 4x4 puts the ecu into a rich mode to help prevent overheat. Only works when in 4wd.

Between 2 and 3 on the top of the intake right up by the head. Thats the gage or idiot light.

#5 that most people don't realize is there is on the back side of the Auxiliary air valve "cold Idle up doohickey that hangs off the bottom of the #1 intake runner that controls your cold RPM". To even see it you have to remove the access panel in the passenger side fender and jam your head up into the back of the fender to see it.

#6 is the air temp sensor in the AFM

Mine does it as well but not bad enough that I have ever tried very hard to figure it out. I think its an issue with with various sensors getting into a conflict with how rich the ECM is running the main injectors for the temp it sees.


Do you have a K&N? They are known for letting the oil from the filter get on the Air temp sensor and throwing off the reading. Contact cleaner and rinse it off. Just be careful not to get any of the cleaner down into the flap hinge.


The FSM is no help. It has no specific troubleshoot guide for a hesitations while cold. Under its general hesitation section it says check Air temp sensor, AFM, ECM Temps sensor, Cold start timer sensor, fuel pressure and TPS.

Since its only a cold problem From that list you can probably rule out TPS and AFM (as long as the door is not hanging when cold). From personal experience I have not found issues with Cold start timer. I have tested the sensor and run mine with the cold start injector unplugged and still had the problem.

Is your fuel pressure VSV still hooked up? By pass it and run the fuel pressure regulator off manifold vacuum and see what it does. Test that VSV as well. I know mines bad and bypassed. I wonder if when its cold the ECM will prevent the fuel pressure from coming up when it sees the cold start injector on. In a round about way that would make sense under certain conditions.

Like I said mine really doesn't do it very bad so I haven't really tried that hard to find the problem. I really think it may be problems with Lazy temp sensors all not agreeing when cold and causing a conflict in the ECM till it comes up to temp.

Flash319

I would be looking over the coil and wires. When the engine is cold there can be condensation on the coil. This will cause an arc if there is a crack on the coil cap.

dcg9381

Mine does this also on "dead cold" start and I try to pull up a steep hill outside the driveway.
I don't worry about it... Honestly it feels like an A/F issue to me - One way to confirm would be to watch the output of the 02 sensor (there's a jumper in the engine compartment). I *think* it's cold enough that it's operating in open loop on a pre-programmed A/F that isn't quite right.

Could be a sensor as mentioned above, I don't think it's worth chasing.

We're talking about a minor bog here, just a decrease in power - nothing real significant.

all_terrain17

Yes I agree completely. When my mechanic finished my botched HG job, he replaced one of the temperature sensors on the front of the lower intake. Truck throws no codes, but a temperature sensor problem definitely sounds legit.

On cold mornings I get an extremely high idle, but little power. (fault of the cold start bypass valve thing below the throttle body - which I can't adjust because it's been reassembled with loctite at some point. )

On warm days starting cold idle is fine of course, but truck has the power loss everyone talks about most of the time.

So definitely sounds like a temp. sensor somewhere...