1st gear stutter: What could be causing it?

[AG DesignWorks]

Recently, i've noticed a problem when getting my P5 moving from a stop in first gear.

Everyone remembers what it was like learning how to drive stick...you let the clutch out but don't give it enough gas, the car jerks and stutters forward, violently shaking the whole car. Well, i'm having that problem, and i've been driving a stick for over 10 years.

When i take off from a stop sign, if i'm not super careful with how I modulate the gas and clutch, the car will shudder and lurch forward until i give it more gas. However, when i give the car MORE gas from when i first take off, it will still shudder, but just a little. It's very difficult to get a nice smooth take-off with out very carefully modulating both feet.

I haven't really been able to nail down why it's doing this. I think it MIGHT have something to do with the colder weather, but maybe not.

Any ideas? I don't think i necessarily need a new clutch because i'm not getting the usual tell-tale signs that the clutch is going out (over revving in higher gear, etc). Maybe the throwout bearing or something else?

 

[Flash5]

sounds like a misfire in one of the cylinders. if you get a basic tune up it should get rid of it.

 

[reut1]

i feel like I have this same issue. doesnt do it all the time and has only been doing it semi-recently, maybe since the summer. wouldnt a misfire cause a CEL or anything?
now that I think about it, i feel like its been since I put in new plugs. originally i thought it was from a torn motor mount but they are all good

 

[yangsui]

Check for tired engine mounts. Torn front and passenger engine mounts gave me this problem. Doesn't matter how smooth you are with the clutch and throttle if the engine is just flopping around in the engine bay

 

[reut1]

Check for tired engine mounts. Torn front and passenger engine mounts gave me this problem. Doesn't matter how smooth you are with the clutch and throttle if the engine is just flopping around in the engine bay

the only one that I cannot verify is perfect is the rear one. but the front is slightly torn but has a poly insert in it, passenger one is brand new and i recently took out the drivers to inspect and its perfect with no tear at all.

 

[CheeseHelmet]

Could you be experiencing clutch chatter? My car would shudder real bad last winter when I had my old clutch and flywheel, but this year I can take off nice and smooth.

My trick to getting rid of the chatter would be to rev up to a little under 3k before engaging the clutch, does yours still "stutter" when taking off slowly but at high rpm?

 

[AG DesignWorks]

Excellent suggestions, guys.

It very well could be the motor mounts, before I bought the car, one guy told me that the motor mounts are notorious for failing, so i'll get those checked out.

If i rev the engine up much higher, it does it LESS, but there's still a little judder i can feel in the steering wheel. Around town driving, i really don't want to have to wind the motor up to get going smoothly though.

As for a misfire...wouldn't that trip the CEL?

 

[tweety2300]

Does it do it all the time? I also have the same problem but only when its cold once it warms up it won't do it. Could it be the flywheel having a rough surface or the preasure plate? It could cause the symptons your describing but with the clutch disc itsself still good it wouldn't slip. Does it do it if you take off in 2nd or if you don't give it any gas and slowly ease your foot off the clutch untill its completley off. I realise these put unnessecary stress on everything but it could help narrow it down

 

[justanothermp5]

lol...not a missfire, i know exactly what the OP is talking about

sounds like clutch chatter, and that s*** sucks, I get it all the time, and im on aftermarket mounts, and aftermarket clutch
I think its the flywheel, i didnt get the flywheel machined when i did the clutch (dumb i know)
and im pretty sure there is a hot spot on it, which could cause the chatter, or it could just be the clutch design

whenever i get some cash, i'm going to upgrade to a lightweight flywheel and stage 2 clutch, and im steering away from SPEC, ive heard someone resolve the problem with the lightweight flywheel
me and my brother both have the chatter, and we both have been driving stick a decent amount of time, never had it before with the stock clutch though

 

[CheeseHelmet]

My old pressure plate and (to a lesser extent) my old flywheel had a bunch of little discolored spots on them. I'm guessing the previous owner of my car wasn't so gentle with their left foot, I doubt I could make that much of a mess in a few months of regular driving

For whatever reason I noticed the chatter was much worse in cold weather, but I can't remember if it diminished when the car warmed up (something tells me it did).

 

[AG DesignWorks]

I did a good bit of driving tonight in stop and go traffic. It was in the high 40's tonight. I can tell you the car was very smooth before the engine warmed up. I was able to leave stop lights with very little thought into how i modulated the clutch and gas and the car took off smoothly repeatedly.

As the evening wore on and everything got up to good running temperature, that's when i had to be careful with my feet to make sure I got a good smooth take off. I encountered alot of chatter if my feet weren't perfect, and I even notice that i would get a little mini-shudder as I got back on the gas going into second gear.

I don't know if the ambient temperature is part of the problem, or if the problem starts as i heat up the clutch in stop and go traffic. Maybe the clutch/throwout/flywheel is getting heated up with so many starts and stops and that's what's causing the issue. Clearly i'm not getting solid, even power delivery from a stop once the car has been driven for a while.

Any other ideas? I guess I should make an appt with my service guy at Mazda. I worry that driving it this way may be causing harm in the long term. I'm kind of thinking that it would be like the abuse a new stick-shift driver would put on a car. A little bit of practice never hurt, but driving like this every day could certainly wear things out more quickly.

 

[CheeseHelmet]

I even notice that i would get a little mini-shudder as I got back on the gas going into second gear.

You'd get a shudder with the clutch fully engaged (ie. foot off the pedal)?

I worry that driving it this way may be causing harm in the long term. I'm kind of thinking that it would be like the abuse a new stick-shift driver would put on a car. A little bit of practice never hurt, but driving like this every day could certainly wear things out more quickly.

If it is the clutch/flywheel then don't worry about it, it'll just slowly keep getting worse but you won't ruin anything else.

 

[AG DesignWorks]

Not with it fully engaged, but right at the end of the shift into second, just as the clutch travel is almost complete and my foot is back in the gas. It happens at the same time it would in first, but in second, and much smaller because i'm already moving.

 

[yangsui]

Visually inspect the engine mounts first. That costs nothing. No need to wait and pay for a service check at the dealer.

For locations of engine mounts, see attached pdf: View attachment engine_mounts.pdf

The passenger side one is easy to check. Crawl under the car to check the front mount, might need to feel for tearing with your hand. The driver side mount is a little harder to check but it's pretty beefy, if the front and passenger mounts are okay, the driver side is most likely fine. The rear mount is a b**** to check. I don't even know if you can fish your hand back there to feel for tears.

 

[AG DesignWorks]

Thanks for the diagram yangsui, i'll give those a good look tonight when i get home.

 

[MasonMetcalfe]

I had that issue, same situation, front motor mount was shot. Replacing it fixed that.

 

[peter330]

Hey did you ever end up fixing this problem. I am experiencing the EXACT same thing and nothing more nothing less. If you could give us (me) an update with your problem it would help me out a lot to pin point what to fix/replace. Thanks

 

[peter330]

bump on your results

 

[tweety2300]

Have you checked your motor mounts?

 

[jtlinna]

He's LOST IN SPACEEEEEEE!!!..

JT