viku_st

Hi, sorry if this topic was covered already but I couldn't find anything so far.
I will explain in two wards: 1.when I stop very quick, about when I'm stopped,t he car start shakes and a vibration comes from the engine, I notice that RPM goes down as I slow down gradually but when it rich 900-1000RPM (vibration start) it jump to 500 Rpm and again jump to 8-900 and the vibration is gone.
2. I did the same thing with the car in "N" position (neutral), and everything is OK, no vibration, nothing.
At the same time the engine is working a little bit rough, a vibration that was not before.
I have any ideas but better to keep silence than say something stupid. Thank you,

samaritrey

If you are worried about the Rpms getting down to 500 there is a fix. My car use to seem to get down to far after a long run or high speed down to a stoplight. my dealer changed the Idle speed and reset something and i have not had the problem since. they said that nothing was wrong with my car it was just what it liked to do lol and since it made me nervous they changed the speed to keep it around 900 instead of dropping down to around 650 like it use to after the long run.

ok changing ideas how many miles are on your car and what maintenance have you don. (spark plugs, air filters, coil packs, MAF, any sensors etc...)

viku_st

79... miles yes I have the spark plug changed about 4Km ago, mo MAF, but O2 sensor before catalytic converter, lucking to change the bushings on upper control arm, driving really good so far, an I forget, the cam sensor is replaced too. I'm worry about the vibration now, i'll lift the car tomorrow, want to see what should I look for, ...
Thank you for prompt response

OK but did you have the vibration with the jumping Rpm or not? it keeps for about 1-2 seconds ..

Song

I think it may be the way the car drop rpm before changing to a lower gear. The gear suppose to change to a lower gear faster, I think it like running a car slow at a high gear so it shake??.I don't know for sure ..

Glyn M Ruck

Try & get the car onto a Star diagnostic machine to check mixture & idle. Check O2 sensors. They can cause hunting & stumbling of the engine. Have you checked for error codes with an OBDII scanner? Check all vacuum pipes for a leak. Check engine mountings & rear gearbox mount.

If the car is in a good state of tune & you have checked cam sensors, plugs, wires, coils, CPS etc. then the worst thing it can be is a sticking torque converter lockup clutch. I have only experienced this once with member Ichibans.

viku_st

I did not change the fuel filter, can it influence the fuel delivery? and everything related with this? The car was inspected few hundred miles ago no errors, codes.

Glyn M Ruck

The fuel filter will cause trouble as you accelerate & place greater fuel demand on the engine. The pressure regulator is built into the filter. I don't know what mileage it has done so maybe a filter change is a good idea.

viku_st

i have a 79800-80000miles and the filter it's still a factory one. I'm going to change it any way, the maintenance bulletin says at 75,000miles to be changed so.
And by the way: what is CPS?
Thank you Glyn

Glyn M Ruck

Sorry - CPS = Crankshaft Position Sensor.

At your mileage you must change that filter - Good luck!

Capt Nemo o2

It is possible that you have a small vacuum leak and when you stop quickly, the power brake booster is using up all/most the available vacuum and the engine wants to stall.

Glyn M Ruck

+1