[Inais]

Hey all, got an 09 JT GV. 5 speed manual.
Though I'm fairly sure this question might apply to any car and anyone mechanically minded.

Ive got this issue, only not sure how to explain it.
Words like jumpy and jerky come to mind first but I'll try explaining the problem and see how we go. (It could be normal for all I know)

So if you have ever watched a movie and someone is learning to drive manual, you will see what I mean. That off and on jolty, jumpy, jerky movement. Only mine is nowhere near as bad as that, but still enough to irritate me.
Seems to do it more under 70km. Something as simple as accelerator off, then just lightly putting accelerator back on will do it. Between gear changes, around roundabouts. In fact the only time it doesn't do it is if it's given me enough grief that I have given it a gutful and drove race car style.

Now I hope that's given you some idea of what's doing? But I can explain further if needed.

OK. So it's been like this since I got the car, say about 3 months now. 240000km, and bought without books.
Here's what I have tried.

Service - oil (10w 40), oil filter and air
Spark plugs
Intake carb clean
Tire inflation (now the car is rough, no difference)
Air con off (makes a little difference)

I started with the cheap stuff first. I don't even know if I'm looking in the right area.
My next step was gearbox fluid change as it can be a little hard to change gear.

The clutch feels good, and I have driven manuals for years. I do find if I ride the clutch it makes a huge difference between gears and around the roundabouts. But I don't want to be doing that.

Any ideas of where I else I should be looking? Or anyone had a similar problem?

Thank you in advance.

[bumstein]

Hmmmmm.. is it a misfire?

[Inais]

bumstein wrote:

Hmmmmm.. is it a misfire?

I don't believe so. Seems fairly responsive in neutral at idle.

[bumstein]

Firstly I’m not a GV bloke myself and can only comment generally but seeing as no one else has chimed in I’ll make a few comments and hope something helps..

You’ve done several things and all good steps. You haven’t mentioned fuel filter, replacing this is a good easy step to take as well. Make sure the fuel in the car is fresh, yes fuel does go off and old fuel can cause a heap of problems

Now, you can have a misfire under load which doesn’t replicate at idle or when reving the motor, and they can be a bastard to diagnose. The fact you mention that there is a slight improvement when the AC is off might suggest this is the case? Ignition system would be a likely cause if that’s the problem.

Timing out or ignition advance problems?
You’ve replaced the spark plugs with no joy, are you sure the plugs you’ve put in are the correct type and the gaps are set properly?
Also possible to have ignition coil failure or bad earths cause this problem.
HT leads breaking down

A quick google will give you some diagnosis steps to take.

The other thing that springs to mind, and this may not be applicable to you, is blocked carby jets. You mention that you’ve done an “intake carb clean”. Is it carby or fuel injection?

If it is in fact carby and the jets are blocked then this could explain flat spots in the acceleration such as when you lightly apply the throttle but stabbing the throttle full biscuit works ok. If it’s EFI then perhaps there an injector problem, dirty or damaged injectors spring to mind but that’s just a stab in the dark really..

[atari4x4]

I found the drive by wire throttle to sensitive on my 2018 jt grand Vitara, mines auto but I’d guess it would be amplified in a manual

[Inais]

Thank you for the replies guys. Appreciate it.

Firstly I should elaborate a little that the car doesn't feel like it's bogged down, or cuts out, the power is still there. It's just jerky.
I have not changed the fuel filter, so that might be the go. Although I did read some where it's in the tank attached to the pump? Anyone confirm??

It is fuel injected, so I gave all that a good spray, twice actually as I had to take the radiator out since posting.
Have also ran a couple of tanks of injector cleaner and have been using 98 octane fuel.

Spark plugs were definitely correct and gapped proper.

Could be just how the car is going off that last post with the drive by wire?

If I drive aggressively the car is awesome though. No signs of any problem like this.

Thanks again for the replies. I'll have a look more into the fuel filter.

[30ONA]

Inais wrote:

bumstein wrote:

Hmmmmm.. is it a misfire?

I don't believe so. Seems fairly responsive in neutral at idle.

You won't always hear a misfire of its not under load. Put it in a high gear and drive up a hill. The engine will be rough as if you have a misfire.

[30ONA]

Where are you? There are some experienced Suzuki specialists around.

[alien]

My EFI sierra used to do this, but only when doing around 3200-3500rpm and under VERY light throttle. I never really got to the bottom of it, but it felt like a little slack in the cable would have it sort of come on and off, like the spring wasn't able to modulate it in that finer detail with that level of airflow??? Simple solution - go up or down a gear, or just go faster/slower in the one you're in... Unfortunately for me it used to happen right around 100km/hr, so if I had a tailwind on the freeway it was really repeatable. I just did 105km/hr and all sorted lol.

[missmyljdaze]

30ONA wrote:

Where are you? There are some experienced Suzuki specialists around.

Mackay Qld

[Inais]

Thanks again for the replies guys.
Just an update on the misfire. Definitely not. Have tested it on a bit of a hill and goes alright.
If I drive like a Hoon it's a perfect ride. Just chews the fuel.

Another description I might have certain up with is that it feels a bit like the handbrake is stuck on, some sort of resistance. Going to do a tire rotate over the weekend, so I'll check the bearings and what not there as well as free spin.

[Gwagensteve]

The problem is we can't tell what's normal or not from a description. You need to drive a different example of the same car or have an experienced mechanic who has driven other GV's to provide an opinion.

How familiar are you with constant 4WD vehicles? They tend to have a bit of driveline "shunt" or "snatch" which is especially noticeable with a manual. There isn't a fix for this, it's a characteristic of the driveline.