1993 Gs300 Rough Idle Lacking Power

mdm6713 · October 30, 2006

Hey guys..93' gs300 runs really rough. Its pretyy much fine when it moving. Except when it comes to a stop it might stall. well today I put 6 iridiums in it, new VC gaskets, cleaned the intake and egr well.I t runs really smooth at times, then all a sudden it will just start running terrible,...I hooked my timing gun to it and it was all over the place, but the idle isnt consistent so I dont think the reading means anything. Also new wires, cap and rotor, got 167K on this car. I also cleaned the Idle Air Control valve. Check engine is on also but i dont have the tool (yet). Im thinking TPS? (throttle position sensor). Help anybody!

thanks

mdm6713 · October 30, 2006

I should also add about this car....

The plugs (all 6 identical) where covered in soot. fouled out bigtime.

I tried changing the Ignitor, and the Ignition Coil (swapped from my dads GS) No differance

Im pretty convinced the problem is either..

1. TPS

2. o2 sensors

3. Both

4. other :wacko:

The thing that Im hung up on is the fact that is wll run smooth, then all of a sudden start boggin down and acting viotlile, like a man walking down the street in good health, then starts vomiting ramdomly :huh:

This makes me lean toward the TPS since its "intermiddent" or whatever..

Thing is...on a 93' no OBD2...so how do you install it?

Im waiting on a scan tool in the mail now, then Ill have codes, until then...any suggestions would be helpful, Im have the benifit of using my dads car to sawp parts with, although the ICV is differant. The problem car is a CAL model.

please advise

mdm6713 · November 1, 2006

Guys???? Nobody has any clue about this? Has anybody seen the GS300 with an idle that just wont maintain? Its down to practically nothing at time(400 rpm) then maybe bouncing around to 1500 etc etc...any suggestions folks? please!!!

thanks

Michael

mdm6713 · November 21, 2006

Im getting pretty depressed here replying to myself here! Im still having problems with my gs300 1993. Problem is is wont idle, its OBD1. Funny thing is the check engine light and trac light will go on and off, its mostly on at idle when running rough, but if you rev if it, the lights go out. I have dont plugs, wires, car rotor and now o2 sensors, it runs great when it moving, but wants to stall at low speeds and stops. The current codes are 21 28 31 (O2 front,02 right, Vane air flow?) I have no idea what Vane air flow is, I think its the TPS and I have one I can switch out and try, but im unclear of how to install it. Any suggestions?

please advise

Cornwall · November 21, 2006

Hi there MDM

I am over the water in UK but booked in here to pick USA brains as well

So returning the favour I hope

I have had my GS300 Mk1 (same as yours over there) for only a few months, and it had basically sat in the previous owners garage for 4 years and did less than 500 miles in that time

I had bad idling and lack of power as well and stalling although it was ok when I bought the car, it started playing up soon after

I took off the throttle body and it was like a barbeque in there so I took it off, not a bad job to do, all basic unscrewing nuts and hoses, don't forget the water hose half hidden underneath the body but you can get to it

Mark the vacuum hoses with a little tippex or paint to make it easy to put back on

Cleaned it out with carb cleaner and a rag, cleaned out all the vacuum hoses and checked and cleaned the sensors

Now here was the lucky bit I found my problem and my cure by accident

Just after the air filter box is an air sensor it looks oblong and has the electric plug on it, i took that out and couldnt work out how to clean it or what it really did, it is held by 3 phillips headed screws

I reassembled the lot and started it up, and it ran lovely smooth and even and a quick drive and the power was back

Getting back i opened the bonnet and checked the connections for safety and found I hadn't tightened those 3 screws on the sensor, so I screwed them up tight

Back in the car and it ran like a sherman tank, now i thought thats daft what happened ?

The only thing I did was tighten the 3 screws so open the bonnet and slackened them off again and it ran beautiful

i tinkered !Removed! in and out and found just tighteneing them finger tight worked well

Now I am not sure obviously if this is your problem, but thats whjat it was on mine

Good luck

mdm6713 · November 21, 2006

Thanks for the reply. The sensor your talking about is the MAF or the Mass air flow sensor. Im not sure really how to clean is either other than some dilicate solvents to spray in there. As I understand, theres an elment in there similar to wax..its cooled by the amount of air that passes and give that reading to the ECU.

Sorry to say I still have a problem, Im about to go GUN HOE and take the TPS off of my dads car to try to swap it, but im affraid then Ill have 2 broke down GS's!

Anyone familar with changing the Throtlle Position sensor on a 93 gs300 ?

please help!

michael