I notice this happens more often during hotter days and while in either Park or Neutral, the RPMs sit at 1500-1800 RPMs causing this 5.7liter engine to suck up gas like crazy.

There are no mods to this truck. I'm getting a mess of errors because the engine light is on. I'll edit this topic this evening and provide all the codes because I don't have them at this time. One of the errors was Mass Airflow Senor which I replaced and didn't fix the issue.

 

sticking idle air control valve,sticking throttle

Sean

07 4x4 burb

 

Thanks for the info. But how does the heat effect this? We had another 100 degree day yesterday and it ran crazy all day in the 1500-2k range but late in the evening, I ran it for about 30mins with zero issues.

 

what were the codes you where getting?


Sean
97 4x4 burb

 

Here is exactly what comes up,

P0141
DEFINITION
H02S12 heater condition (heated oxygen sensor-Bank1 sensor 2)
PROBABLE CAUSE
Faulty H02S12 Bank 1 Sesor 2
Poor connection at oxygen sensor
Check circuit fuses

P0174
DEFINITION
Fuel trim bank two conidition
PROBABLE CAUSE
If bank 1 and 2 are set together suspect a fuel pressure condition or MAF sensor fault.
Failed H02S21 Heated oxygen sensor, bank 2 sensor 1.
Ignition misfire
Fuel injector problem
Engine mechanical condition

P0101
DEFINITION
Man. Absolute Pressure/BARO Mass Air Flow/VAF Vane Air Flow sensor
PROBABLE CAUSE
Vacuum hose off, cracked or passage blocked.
Throttle body instake tube loose, off or cracked.
BARO (barometer) MAP Manifold absolute pressure defective
VAF/ Vane Airflow or MAS Mass Airflow sensor defective.


I've already replaced the MAS and though I have the actual service manual, I cannot locate the vent hose.

 

from all of those codes it sounds like it could be a number of things. its obvious you have a bad 02 sensor when it comes to a heater circuit code but that wont effect the performance that much. its ether the map/tps sensor going haywire which I would suspect is the problem but you can also have an air leak. as in your intake manifold gasket can be defective once the engine gets nice and hot and will cause it to suck air causing the idle to shoot way up. under normal conditions have you ever disconnected the air line from the brake booster? same thing happens, major jump in idle. next time your idle is up like that, pop the hood and see if you can hear an air sucking sound.