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tims auto repair
tims auto repair, mechanic
Category: Toyota
Satisfied Customers: 15928
Experience:  owns a repair shop....25 years
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code P0300,P0301,302,303,303. come up only on cold start after

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code P0300,P0301,302,303,303. come up only on cold start after warm up car runs good

Hi,My name is Tim,

I will do my best to assist you

from the way you explain sounds as if you may need to replace the plug boots,,this is what comes from the coil and covers the plugs,,these will get old and jump a spark sometimes



Customer: replied 3 years ago.

The coils were replaced with new boots attached. The motor stutters on start-up with decent idle speed butthe idle goes down so low that multiple missfires occur. By pressing on the accelerator and holding above 1,000 rpm for approx a minute and the engine warms missfires cease. I am using a scan tool.

what may be going on here,,is the ect[engine coolant tempeture]sensor..the computer may think the engine is always warm,,thus,not giving it enough fuel when warm
Customer: replied 3 years ago.

There is movement of the coolant temp according to the dash gauge and the scan too. I am not next to the car now however i could get the readings in approx. 30 min..

another thing you may want to try to remove and clean the iac[idle iar control]motor with carb cleaner,,these can get dirty with black soot and cause this

Customer: replied 3 years ago.

I'll check it out. By the way the car has only 25,000 on it!

but,it is 11yrs sure also to check for vacuum leaks

Customer: replied 3 years ago.

I've cleaned the idle air control. It worked better but the final test will be tomorrow morning. thanks for your help so far.

you are very welcome
let me know how it gos

Customer: replied 3 years ago.

I started the car up earlie and the initial idle was approx. 1200 rpm and it declined to approx. 900 in about 15-20 sec then declined to under 600 rpm and began to stumble.. When restarted with my foot on the accel. for about 30 sec it ran fine and now that its warmed up it starts fin and idles fine. A side note..if i put the ac on it runs better so i'm thinking of replacing the iac. Your thoughts? So far you're helping alot and am very well satified. is very possible that the iac is bad....
replace it

tims auto repair and 2 other Toyota Specialists are ready to help you
Customer: replied 3 years ago.

Because of the price of the throttle body and iac which is built in unlike the diagram pictured, it was not replaced but entirely cleaned.. The car started great and ran great for two days. Now, one and a half days later the problem is back. Any other ideas???

sense the cleaning did help...there is a high possiblility you may in fact need to replace it,,try cleaning it once again..but,,expect to buy one
Customer: replied 3 years ago.


The repair to the toyota was to drain the gas tank and clean the fuel line and all. thanks for your aid.

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