2000 4runner - hesitation/sputtering during warm up

Hello,

I have a 2000 4runner (2.7L - 4 cylinder)...

Recently I have changed: MAF, plugs, coil packs, valve cover gasket and O seals, idle control valve (OEM), throttle position sensor, both 02 sensors (oem), 2 temperature sensors, fuel filter, air filter, cleaned throttle bottle, and check for vacuum leaks

PROBLEM:

When the vehicle sits for a while (especially overnight)...it always starts fine.

BUT....

During the 1st 10 minutes of warm-up..if I step on the gas when it's in PARK and hold it about
1500 RPM...the truck will sputter and the RPMs will fluctuate up and down

Also...if I try to put it in drive during this time...and then step on the gas...the truck will hesitate, sputter and even stalls out.

From the time I start the engine ....it takes 10 minutes for the temperature gauge to move from Cold to the midway point (between cold and hot)...

Once the temperature gauge reaches the midway point ..it seems to run just ok (especially
after I get it past 2000 RPMs). But...there is still some hesitation though when I acclerate after
coming to a full stop.

Anyone have any ideas? Again..please see the list of all the items I changed...

Thanx!

 

I'm just learning my way around the 3rd gen 4Runners myself. Having said that, did you perform the TPS alignment according to the FSM, or just put a new one on? By the "idle control valve", did you mean the IACV? Did you check the ETS for the correct output? The Engine Temperature Sensor. Did you clean the temperature sensors' threads? That is their circuit's ground, and needs to be very clean when you put in a new one. NO Teflon tape on them, either.

Did you check the wiring from the various items you changed to the ECU, or whatever places they might go? No pins pushed in the various connectors, and the connector pins, male AND female, nice and clean? Maybe a dab of Silicon Dielectric Grease in them? And so on...

Did you change out the plug wires, when you replaced all the rest?
How about the injectors? Did you check their operation, as well as their various ohm readings? All their plugs nice and clean, nice and tight?

I'm just shotgunning. I hope something I mentioned might help a little...
Pat☺

 

Any codes? Any Pending codes?

Sort of sounds like fuel pressure isn't too good. Might be a bad fuel pump or a sticky fuel injector or two.

Electrical issues/sensor issues are often hesitation issues, maybe surging, but not so much "sputtering".

-Mike

 

Check for vacuum at the fuel pressure regulator?