Toyota Yaris 1999 --engine starts to shake

[kevin888]

Hi,
The engine on my Yaris 1999 starts to shake. when it running in idle mode, I can see the exhaust outlet uneven. I have change all 4 spark plugs to new one. But not difference. Any suggestions before I take it to the repair shop?
Kevin

[Freedomage]

Have you cleaned MAF sensor lately?
How about performance, is there any decrease of performance?
If there is, you may need to unplug sparkplugs one by one and check engine sound. By the way if you need to do this You'd better use rubber glows to avoid electrical shock!