bogdann

My auto will stutter while I am stationary with the auto in 2, 3 or D. I thought it was the engine but I feel it in the rear and when I put it into neutral there is no stutter. It will start with one blip and the longer it is stationary it builds to the point I think it is going to stall. Usually when it is warm and after a string of lights or stop signs.

I am losing fluid from the seals and need to remove the auto to fix but I would rather fix this issue also before I put it back in.

Any known cause for this issue, other than running red lights and stop signs?

Thanks

auzivision

Never heard anyone describe a transmission stuttering while stationary. When I hear terms like stuttering and stalling, I think engine... which makes me think spark or fuel. So many choices too; for example, vacuum leak, faulty wires, aging maf, crappy fuel, and so on.

For what it's worth, my transmission has had a small leak off and on for going on about 10 years now. Used a product called Trans X about 5 years ago and it didn't leak until recently. Not a major leak, just an ounce or so a year. Keep it topped off and besides the mess, everything is good.

WallyP

Perhaps the "stutter" is the engine - no stutter in Neutral because there is less load?

Check the idle speed, use a hose to listen for vacuum leaks, check the coils, coil wires and plug wires, etc.

karl ruiter

My '88 does this as well, but I think it is that the idle speed is too high: Enough so that the tranny is actually trying to move the car forward which I am preventing with the brakes. So the motor is pulling against the brakes.

GregBBRD

Can you explain a bit more what "stutter" is?

Misfire in engine?

bogdann

It sounds like it is poor leads, fuel or vacuum but it "feels" like it is coming from the rear of the car not the engine. Also the engine doesn't miss a beat when idling in neutral or park and drives hard through to 6000 rpm. Usually if I have had a bad lead or plug it is a bit more consistent in how it misses but this is random. The longer it is held the worse it gets, not when cold but after it has come to full operating temperature. One little stutter/stumble becomes 2, then 4 and builds to many stutters/stumbles over 5 seconds then settles for a little before it starts again. It has never stalled while stationary or as I have accelerated from the stop.

New leads, coils, dist caps, new ignition switch, ISV, fuel pump and fuel filter etc with top end refresh. All earths cleaned. Idle is running at around 670 rpm.

I will check leads etc again and make sure the idle is set correctly. It may be high as I do have to apply the brakes to hold it at a stop. Will also check the vacuum again.

Thanks for the help.

GregBBRD

O2 sensor?

WallyP

The dash tach may not be accurate, especially at low revs.

James Bailey

Keep in mind it is summer time in Perth high 80s low 90s odds are he has the A/C running....go back to basics and reset the idle speed while jumpering off the idle stabilizer valve. Then see if the computer can hold the idle speeds.

bogdann

Yes the O2 sensor in the last 3 months, idle off a meter, not the dash and it is pushing 100 - 105 deg here at the moment so definitely using the air cond. I get the idea it is the engine and not the auto.

Will check the connections, vacuum and idle soon as I have to do the WP/TB job.

Thanks for your help.

Yves from France

Hello

This thread is about 9 months old and I was wondering if bogdann (or anyone else) had ever managed to find the fix to this issue?

I have a 1985 S2 with 4speed A/T and I have exactly the same problem :
- happens when engine is warm, not cold
- idle is perfect when in Neutral or Park
- but when I'm in D (or 2,3 or R), waiting at a traffic light for instance, it feels like the "clutch is not fully disengaged" (I realize it's not a very good comparison since it's an automatic transmission, but that's how best I would describe what's going on if I had a manual transmission... hope you see what I mean) : The car tries to move forward, but obviously can't since I'm holding the brake, so the idle goes down because of that "clutch not fully disengaged" impression, and the car eventually stalls.

Could it be a symptom of a faulty torque converter (hopefully not ...)?

Someone above was talking about a possible vacuum issue. I have a mytivac so could easily test that, but I'm not sure what / where I'm supposed to check?

Thanks much in advance for your help !

bogdann

Hi
I ended up increasing the RPM slightly which did solve the problem. I knew if I was sitting at the lights in gear I would solve it by touching the accelerator slightly to increase revs. Issue has not come back since.
I am doing WP/TB with fuel dampers etc.

Yves from France

Hi Bogdann

Thanks for the update. So when you say "if I was sitting at the lights in gear I would solve it by touching the accelerator slightly to increase revs"... do you mean you have one foot on the brake and the other one nudging the accelerator at the same time? That's a bit counter-intuitive but interesting, I should try that.

Also, what does WP/TB mean? I'm just not familiar with the acronym.

Thanks again !

bogdann

Hi
Like a heal / toe manoeuvre. You just need to get the revs up 50-100 rpm which stops that feeling the car wants to stall. It isn't a long term solution!! Also mine never stalled but it feels uncomfortable sitting in a line of traffic wondering if it will stop and if you can get it started again. Check what revs yours should be for your model.
WP/TB is water pump and timing belt replacement.
Regards

Yves from France

ah ok got it, thanks ! I will definitely try that.

I'm still wondering though why in that case I have no issue when the car is in N (in that case the revs are around 750-800 and very stable, which is line with the specs - but they go down to oscillating between 550 and 700 when I'm in D which is my issue). Before I got this problem, the revs were the same either way.
Put otherwise, if the root cause is that my idle is setup too low, then it would be too low when I'm in N as well, wouldn't it?

As said I'll definitely try what you've done but I'm curious to better understand the theory behind the issue and the relationship between the idle rev on one hand, and the D or N position on the other hand.