I have a 1997 rav4..4cyl stalls when taking off from a stop.i have a scan tool.at idle engine load % is 30-40..tps % 19 no codes.happens more when cold ant turning.it stalled today, and rolling nuetral took to long key cycles to start.closed loop, goes open loop when you release pedal at times. is it the tps or what? calc engine load never goes 100. help pls. i have rnr t-body and cleaned idle valve real well. i have not come accross closed loop going open loop when you come off the throttle. or even some advice to try this or that. i am a tech by trade. So i have all the test equipment. i'm hoping someone has seen this problem.

Is check engine light on? If so have scan tool put on it at auto parts store. Get codes and google search the codes. Could be IACV (idle air control valve) or TPS (throttle position sensor) .

Clean the throttle body bore and plate and the idle air control valve .

fuel filter is somewhat built into the pump and installed within the tank. Periodic replacement isn't necessary and I'm sure the filter itself and getting a mechanic to drop the tank will be very expensive.

what did you do with a "tune up" ? gotta go retrace your work and make sure the plug gaps are correct etc.

if a check engine light went on after your "tune up" then you need to find the trouble code with a scanner and that will help you in the direction you need to go. Free trouble code scan at my local autozone or advance auto parts or even aamco transmission shops

hot engine or cold or both, just a clue here.
wow gue$$sing is expen$ive.
is the CEL lamp glowing ever running,, YES?< then scan it.


ok so it stalls.
after the skipped 60k mile tuneup is done
if it still stalls.
so you use the right foot action fast acting at stall...?????
and you can prevent the stall easy.
1: very easy, iSC stuck closed or throttle idle detection is bad.
2: harder to stop stall but can , EGR leaks, main EGR valve.
3: impossible. this is gross spark failure ,or loss fuel or flooding

see how far you get on my list. and post back.

first ,now how the EFI works not guessing
it tries all the time to prevent stalls if it cant prevent it, it does stall.
rule2, the ECU controls idle speeds at all times the ISC is the slave to that..... so if the ECU open the valve and the stall gets worse.
its not the ISC/ECU fault. its fueling or spark.
a lean engine stalls. if lean enough ,no ISC can stop that.
a misfiring engine stalls, too.

a tech, dont attach the ISC< no he does not
he looks at spark an fuel rates. using , a scan tool.
The ISC can not cover the bad tracks of bad fueling and spark
nor a stuck open EGR.
THE ISC is dead if the TPS is set wrong, and the ECU thinks wrongly
that you are not at idle. so the ECU cuts idle controls

I use my scan tool to watch the, for error,s DTCS,. and pending errors
and watch for closed loop at idle. hot.
if it is in close loop at idle and it stalls then the ISC is failing
if rigth foot can save it easy.
id bet the fueling and spark are bad or TPS not closed, signalling close or the EGR is stuck wide open'

btw., if eCU drop s to limphome mod (scan it) it will infact drop all ISC
idle controls..

we look for the true cause, do tests, then replace parts
never the reverse or go broke fast.

try using a scan tool to reset the ECM program after disconnecting the battery

Have you had it to a shop that has a professional type scan tool that can view engine sensor data parameters ? Do you know what those are ? Idle air control counts , mass air flow sensor data , MAP sensor , TPS - throttle position sensor , crankshaft position sensors , Cam sensors , engine coolant temp , intake air temp etc......

P0121 The Throttle position sensor is a potentiometer that measures the amount of throttle opening. As the throttle is opened, the reading (measured in volts) goes up. The powertrain control module (PCM) supplies a 5 Volt reference signal to the throttle position sensor (TPS) and usually a ground also. A general measurement is: at idle = .5 Volts; full throttle = 4.5 Volts. If the PCM detects that the throttle angle is greater or less than it should be for a specific RPM, it will set this code.
Potential Symptoms Symptoms of a P0121 trouble code could include:

• Malfunction Indicator Lamp (MIL) illumination (Check Engine Light or Service Engine Soon light)
• Intermittent stumble on acceleration or deceleration
• Blows black smoke on acceleration
• No start

Causes A code P0121 may mean that one or more of the following has happened:

• TPS has intermittent open or short internally
• Harness is rubbing and causing an open or short in the wiring
• Bad connection at the TPS
• Bad PCM (less likely)
• Water or corrosion in connector or sensor

Possible Solutions 1. If you have access to a scan tool, see what the idle and WOT (wide open throttle) readings are for the TPS. Check if they're close to the specifications mentioned above. If not, then replace the TPS and re-check.

2. Check for an intermittent open or short in the TPS signal. To do that, you can't use a scan tool. You'll need an oscilloscope. The reason is because scan tools take samplings of many different readings over just one or two data lines and can miss an intermittent drop out. Hook up your oscilloscope and watch the signal. It should sweep up and down smoothly with no drop outs or spikes.

3. If no problems were noticed, perform a wiggle test. Do this by wiggling the connector and harness while watching the pattern. Does it drop out? If so, replace TPS and re-check.

4. If you have no TPS signal, check for 5 Volt reference at the connector. If it's present, check the ground circuit for open or shorts.

5. Make sure the signal circuit isn't 12V. It should never have battery voltage. If it does, trace circuit for short to voltage and repair.

6. Look for any water in the connector and replace TPS as necessary.
P0068 Symptoms - Engine Light ON (or Service Engine Soon Warning Light)
- Lack/Loss of power
- Engine rough idle Possible causes - Large vacuum leak
- Leaking air duct system
- Mass Air Flow (MAF) poor electrcial connection
- Manifold Absolute Pressure (MAP) poor electrcial connection
- Faulty Mass Air Flow (MAF) sensor
- Faulty Manifold Absolute Pressure (MAP) sensor
- TP sensor not seated properly.
- Faulty Throttle Position (TP) sensor.
- Dirty throttle body
When is the code detected? The Powertrain Control Module (PCM) monitors operation rationality check by comparing sensed throttle position to mass air flow readings
P0068 DODGE Description The Powertrain Control Module (PCM) monitors a vehicle operation rationality check by comparing Throttle Position (TP) to Mass Air Flow (MAF) readings. If, during a self-test, the comparison of the TP sensor and MAF sensor readings are not consistent with the calibrated load values, the test fails and a diagnostic trouble code is stored in continuous memory.

First of all have you done obd2 scan test for codes?

Have they checked your TPS sensor as this is the most common cause for rough idles and stalls...

Try looking for engine vacuum leak,around the injector seals inlet etc.Is the air box lid and hoses tight and leak free?Could also be fuel pressure problem Try squeezing the fiel return line with the appropriate tool so you dont damage it and see wether the engine idles properly.If idles better more than likely fuel pressure problem.