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GazJenno

Stuttering/stalling/hesitating Gs300

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Hi all,

My dad has recently bought a GS300 Sport that seems to have abit of hesitation when pulling away. I also noticed that under very light throttle with abit of load the car stutters and revs go up and down as if it doesnt know weather to go or not. It has also stalled on me once when stopping at a junction. Hoping someone on here may be able to help as it seems to be one of thoes problems that comes and goes and could be caused by a number of things :(

I have checked fault codes on the ECU and none were found

Pulled a plug and they are quite clean NGKs

Done oil change

Done air filter change

...thinking maybe MAF sensor? Fuel pump/fuel filter? coils...are they coil packs on these? maybe needs a gearbox flush too?

cheers,

Gaz

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doesn't sound like the gearbox, leave that alone for now.

Each plug has it's own coil pack. Does the engine idle ok with the air con switched off?

Is the engine check light on? Ideally need to know if an error code has been logged by the ECU.

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doesn't sound like the gearbox, leave that alone for now.

Each plug has it's own coil pack. Does the engine idle ok with the air con switched off?

Is the engine check light on? Ideally need to know if an error code has been logged by the ECU.

yea idle is fine... drives fine most of the time but the hesitation from stand still can be abit sevre at times, must add that the gear oil does look abit brownish. I was going to change it my self but not much point as you can only replace 2.4litres and the box holds 8ish litres so will most probably have it proffesionally flushed.

I have read the ECU and all is good no error codes on any of the systems and all the actual values from the sensors seem good. Was wondering is the throttle butterfly operated by cable or does the cable just provide information for a throttle butterfly motor?

cheers,

Gaz

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dirty injectors? they may be self cleaning but my dads carina had exact same problem as your dads gs300. turned out to be a injector no:4 being faulty!

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the throttle cable is just there are a backup to the electronic throttle. The cable does actually move the throttle butterfly but at a much slower rate than the motor. If the motor fails you have a big power reduction as the cable only opens the throttle about 30%.

I've never seen a GS series II transmission with anything other than very clean red fluid. I would get it flushed and make sure you use Toyota T-IV fluid.

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Did think dirty injector so will try abit of injector cleaner and some V-Power, dont think this is going to solve the problem but might as well give it a try.

Colin : I have notice, since you said about it, that after driving then coming to a stop like at a junction the car sometimes stalls but everytime it has done this the aircon has been off! It has not stalled when coming to a stop with the aircon on!... not to sure what that would mean to you but you did ask about the aircon?

I will be getting the gearbox flushed professionally and will make sure the right fluid is used, weather this is the fault or not I still think it needs doing.

You saying about the throttle motor has also made me think because when I was using the Bosch KTS to read the ECU I noticed that with the ingnition on reading the actual values, when I put my foot flat on the throttle so it could go no further it was only saying it was 79% open??? could this indicate a throttle position sensor fault? faulty throttle motor? I suppose this would cause hesitation due to the motor not reacting as quickly, but like I said no fault codes? and why would either of the above cause it to stall... maybe the motor not being able to open the throttle enough for idling?

I'm puzzled ... so many possible things and no definate indication on whats at fault, a long and potentially expensive process of elimination.

cheers again guys,

Gaz

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When the aircon is on the engine idle speed is increased to compensate for the additional engine load and therefore it is much less likely to stall due to low idle.

I would recommend the throttle body is cleaned and the throttle position sensor is checked for adjustment.

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When the aircon is on the engine idle speed is increased to compensate for the additional engine load and therefore it is much less likely to stall due to low idle.

I would recommend the throttle body is cleaned and the throttle position sensor is checked for adjustment.

ahh right yea, the aircon thing makes sense.

Ok I will try cleaning the throttle body as soon as I get chance. To adjust the throttle position sensor should I just look at the Volts that its giving at fully open and adjust it until it actually gives its maximum voltage, would this be 4.5volts? what should it be at when closed? 0.6v. Or is this not a very effective way of adjusting, I no longer have the bosch KTS available to me as well btw.

Cheers again, hopefully were getting somewhere.

Gaz

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Thanks for that... will come in hand, pitty I dont have the KTS available to me now to check the actual values. Wonder if it can be done by monitoring the volts.

I still cant see why it wouldnt give a fault code if its the TPS or Throttle motor... if the motors not keeping up with the pedal position sensor the TPS would pick that up and should give me a code. Will clean it all out tmoz and watch whats happening with the opening and closing of the throttle butterfly.

Gaz

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Have a look for any loose or disconnected pipes as well.. also the condition of them, (brittle, cracked)

John

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Have a look for any loose or disconnected pipes as well.. also the condition of them, (brittle, cracked)

John

Watch for pipes with length-wise cracks too.. tricky to spot when cold if you don't bend the pipes right. Just remove all vac hoses (thin rubber hoses) and replace, looking for condition as John says.

Sounds like air leak post-MAF.

Does it ever misfire through the revs under throttle? coilpacks... or spark breakdown anyways.

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I can feel your pain and frustration.

I had a similar problem recently with my MK1. Check out my recent posts and you will find out how I cured it.

I didn't have any error codes showing either.

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So what's solution for the idle issue? 

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