How can I tell if my car is misfiring?
 

I posted here a couple of months ago that my car judders back and forth when driving...this happens randomly, sometimes not at all if I drive and it can happen when I drive later during the day.

Some users here suggested it may be an engine mount, the garages don't seem to notice anything wrong. So is it possible it may be misfiring or something along those lines?

Here are the symptoms of my car:

- Judders back and forth when driving and stationary
- Opening bonnet I can see the rocker cover box vibrates now and again which causes the car to judder
- Opening the gas value under the bonnet...the engine moved towards me then back to its normal position once I put back the gas valve.
- The rev meter works fine.
- When the car is stationary I can feel the car vibrating very slighhtly.
- When driving at high speed the seems to be little or no judder, the car judders more at lower speeds.

Any other things I should check would be helpful, thanks. So is this a misfire, mount or something else?

checked the coil pack and plugs are clean and tight?

If it misfires, you really will notice it. If your driving along in gear, the whole car will shake. When my car miss fired it was becuase the coilpack had water in it.....

Nope, I have no idea where to find those unfortunately.

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how bad is this judder and where u feeling it from? e.g just the steering wheel?

what car is it? what engine is it?

shoot it and if you miss your misfiring.....




bit more grown up checked the spark plugs, coil pack??

No...I can feel it when I sit in my driving seat.

VTR 1.6, 2001 (Y reg)

mine does this randomly sometimes too.. usually when i am de-celerating...

good service should fix or what?

very difficult to diagnose without seeing the car but from the way you describe the fault it sounds like it could be the engine mount on the drivers side under the ecu. (usually the bolt that goes into it from the bottom snaps).

a diagnostic check should show a misfire up.

you can normally tell on idle if you slowly press the accelerator you can norally tell the change in tone

It does sound like a misfire to me. Main culprits are likely to be sparkplugs, HT leads or coil packs.

check the coil pack i had same problem even ticking over the engine shaking well the whole car no power and if you are reving it give the pedal quick bursts u will notice it wont rev properly

i have the same problem with me 1.4i saxo, iv changed the 4 spark plugs and changed the coil pack for a vtr one and still have the same problem :S bit confused on what to do my car sound like a f**kin hellicopter LOL any ideas???

Check coil pack, HT leads, plug caps if all fails turn to timing! but i highly doubt timing if its still running imo

Check your plug gaps.

sounds like one of the sensors in the t.b to me. give everythign a clean ad replace your sparkplugs just to be sure see if that helps at all.