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View Full Version : Rough idle when hot


Ravnica
12-16-2016, 08:37 PM
I got my alternator repaired recently and since then my cars been very rough on idle when hot. I've disconnected the alternator and the problem is the same and also I've changed the spark plugs. it's charging at 13.5-13.7 roughly with a full load. The battery is new, belt fitted on it today. Internal heater not working though I've replaced the thermostat (probably a clogged internal heater). Coil wires are all fine i've checked them all 3 times. The engine light is on and it gives multiple misfires on all cylinders. then then next day it gave individual misfires for each cylinder 1,3,2,4.

On cold it works perfectly. When hot and the engine light comes on it works normal for a while then it goes chugga again. sometimes when coming to a stop it cuts out (1 in 50 stops roughly) unless I go to stop when going under 2k RPM roughly. when it cuts out (stalls) my power steering goes and my breaks if I release them and press them again theyre much tougher until I turn it back on.

Car turns on fine, as normal as always whether hot or cold. Brought it to 3 different mechanics - noone knows what it is. Won't go to another mechanic until monday so I thought i'd ask and see if there's any recommendations.

please keep in mind I'm not a mechanic though I'm not unfamiliar with the general in's and out's.

I'm driving a 2001 Toyota Yaris with 170K miles.

Bluevitz-rs
12-17-2016, 10:27 AM
Check for vacuum leaks.

Motzking1
12-18-2016, 06:29 PM
Can you give me more info on codes present? The code numbers. OBD codes, manufacture specific codes. What kind of code reader you are using?

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Motzking1
12-18-2016, 06:33 PM
What Bluevitz-rs is saying about vacume leaks makes sence. There should be more information present in the ECU and available with the proper tools. In addition freeze frame data would give another layer of information.

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CoryM
12-19-2016, 03:38 PM
A few people have broken the VVT solenoid when changing belts so that is the first place I would look. If the cam timing is off, you can get misfires/stalling.

If VVT is OK: clear the DTCs, drive it, scan for DTCs again and let us know what pops up.