misfire on no 1 cylinder

[beemer dave]

Since I bought this 1.0 01 car, the engine management light has been on.
Diagnosed on basic machine as misfire on no 1 cylinder. Checked coil which is fine. New plugs fitted and currently trying injector cleaner in fuel.
Wonder if its a sticky valve. Idle is rough and doesn't pull away cleanly. Its fine and smooth above around 1500 rpm. I'm a bit lost as to what to do next apart from expensive trip to main dealer!

[jambo101]

If its got a check engine light on then it should be throwing a code to the OBD11 computer ,plug in a code reader and see what code is showing up.
not sure how you know its the No.1 cyl giving problems but if you've changed Coil,plug wire and plug it may not be the problem,a bad valve would either show some smoke blowby through the exhaust or oil contamination of the plug or it would be making some kind of noise.

[IllusionX]

missfire code can also mean it's not firing at all. Upon a cylinder not working, IDLE will be rough, car will lack power and gas consumption will raise.

that's all i can tell.. i guess..

[cleong]

Isn't the 1 litre a 3 cylinder engine? If it is, you're running on two cylinders...

[jambo101]

Isn't the 1 litre a 3 cylinder engine? If it is, you're running on two cylinders...
Your math is 100% correct:biggrin:

[IllusionX]

looks like the 1SZ-FE is a 4cyl engine!

[cleong]

Yes you're right, its a 4 cylinder - I got it mixed up with the 1 litre the Toyota Aygo has!

[severous01]

hey, how about checking your valve and lifter lash....it's on the hood. you need a feeler gauge.

[TheSilkySmooth]

Do a compression test first. Also, The coil may look OK and have the specified impedance but still be bad due to dielectric breakdown. Luck on this one, mate.

[drifto]

map sensor output would be a good place to get a better idea of whats causing a misfire. if only one cyl. is misfiring... fuel psi/ clogged injectors and egr port clogging are unlikely but not impossible, however ignition side issues (coil pack/plug) or vacuum (bent valves) issue could be a more likely cause. there must be a diag troubleshooting chart for misfire on cylinder 1 in the service repair manual. if not check injectors, swap cyl 1 with cyl 2 and see if the misfire switches cylinders as well. do the same with the coil packs and spark plugs. those are some simple quick checks. then try a leakdown test on the misfireing cylinder see if its out of spec. good luck!