Toyota grande rpm fluctuating

[pwuser155672820957]

I have an altis grande cvti. Recently i have been facing fluctuations with my cars rpm.

1. When i am driving at low rpms (1000) and low speeds my cars rpms would automatically go to 2500 rpms as if car gave it self a down shift and started acceleration

2. When i am driving at a constant speed my cars rpm would go up and down by 200(two hundred) rpms.

3. When i come to a stop 1 out of 10 times my car would show slipping transmission as if it did not shift to gear 1 (although there are no gears in a cvt) and it seems like i am accelerating at gear 3 i.e more rpms lesser acceleration.

4. Sometimes my car gives minute jerks at 30-40 speeds like it shakes forward and backward.

Can any professional suggest me whats wrong and why would this happen? Secondly how should i start its diagnose

[hash4u]

How much is this car driven in total
& What mantainance work has been done last

[pwuser157658581875]

These signs do tell that cvt is having some issues.Try checking cvt fluid when was it last changed.Also mileage kia he gaadi ki

[pwuser155672820957]

Car has been regularly maintained. Cvt oil changed as per standard procedure 10k kilometers ago. Car has 87k kilometers on the odo. What recently happened was that i had a bad engine coil. Got it replaced by a new original one. I’m expecting others to be weak too. When i took out my coils and inspected the spark plugs 3 of them had compression leakage signs (brown oily colour behind the electrode) and the one with the bad coil was as good as new. No compression leakage sign.

[haseeb.basharat]

Check your spark plugs and coils again.
Brown color behind plugs is known as corona effect. Google it.

[usmanhks]

it might be a dirty throttle body.

[Naweed]

apparently it seems TPS is at fault, if altis doesnt have TPS then it must be having IACV, did u recently get any tuning done or removed battery lead or the problem started after a car wash

the other area might be a vacuum leak

plugs or coil shouldnt raise rpm
CVT down shifting is possible if fluid pressure is varying or oil is thick, still not a likely symptom

[haseeb.basharat]

Well that can only give issues on idling.
My car did the same on 22000kms. Turned out that plugs were bad and misfiring.

[Naweed]

try using AC on idle if rpm r stable then u may rule out IACV / TPS

[Naweed]

and no ECL (engine check light) ?

[pwuser155672820957]

Yes corona effect exactly. Why does it happen and is that an issue or not?

Got throttle body cleaned aswell. AC on idle barely increases rpms by 50-100 not more and gets stable again.

Secondly @haseeb.basharat did you get acceleration issues aswell? Like point number 3 in my original querry?

[haseeb.basharat]

Yes it is normal.

Secondly @haseeb.basharat did you get acceleration issues aswell? Like point number 3 in my original querry?

Nopes but I was getting extreme jerks at all speeds.
Felt like cvt shuddering, but engine was fluctuating a lot which made cvt adjust again and again.

[pwuser155672820957]

Yes this is exactly whats happening. Well then i guess i should start with the engine coils and spark plugs. I doubt the engine coils because i recently got new spark plugs installed they have been driven around 6-7k kilometers only

[hash4u]

my friends mechanic put his land crusiers gear box down
issue was in turbo in the end
(diagnosis screw up example)

lot of fake plugs and crap in market. install back ur old plugs if possible and check

[pwuser155672820957]

Can anybody tell me how can i check if my engine coils are bad or not? Like weak or not? What i just noticed is that my rpms fluctuate during idling aswell. I would definitely change the spark plugs aswell

[Naweed]

there r few ways
. remove connector of coil one by one .. the bad coil wont make a difference in engine idle .. good coil will further rough the idle
. replace bad coil with good coil and if same happens then coil is bad else the plug or current curcuit is bad
. remove coil : check resistance where connector is attached .. it should be under 1 ohm typically
. there is a primary circuit in coil as well its resistance varies with make and model but u can test all coils and the one with relatively high resistance is bad .. use multimeter from one pin of connector to the end which which fits the plug .. do it for both pins .. note readings

u can check injectors as well by removing connector
a bad coil usually goes brown (burnt) from plug side

[haseeb.basharat]

Have you changed its plugs yet?
Please do if you haven't, I changed them too at 85000kms. They were about to end at that mileage.

[pwuser155672820957]

I have changed the spark plugs recently. About 10k kilometers ago

[haseeb.basharat]

And when did this problem start? After changing plugs, or changing cvt oil?
Do you have old plugs with you?

[pwuser155672820957]

Got my engine coils changed. Bought the kabli ones and the car is perfect now.