Toyota Repair: Rough start and hesitation in morning, compression issue, coil pack

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Hi,
I have a 2000 sienna van and It starts rough in the morning and ocassionaly hesitates between 30 to 45 mile speed. After 2 minutes of roughing it is fine.
Once the engine is hot the next start is smooth untill next morning.

I got P0300 code from the scanner and it means randon misfire. Any idea what could be the problem. Where to look for problem.

It misfires only when the engine is cold

thanks for your help in advance.

Sufi


Answer -
There is a service bulletin addressing this condition, one or more of the coil packs is malfunctioning, they are located on top of the spark plugs on the front bank of the engine there are three coil packs that fire all cylinders(two cylinders per coil pack)ask the toyota dealer to look up the bulletin and diagnose which one of the coils is causing the problem, and replace it.


Hi Ted,
Thanks a lot for this info.The car was at the dealers shop and he checked the coil packs/switched them around and said that they are fine. He also emptied my gas tank to see if there was any water. He also put some dry gas in the tank and sent me home.

Total $300 bill and still they could not find the exact problem.

Answer -
Do you still have the same problem?


Hi Ted,

I still have same problem. Could this be a mechanical problem. May be  compression issue/ valve bleding etc.

I have checked plugs/wires/fuel pump pressure/filters/sensors etc.

thnx
Answer -
Have the compression tested, there is also a remote possibility that there may be a problem with the ECU or the injectors.

Hi Ted,

I took the car to a mechanic yesterday and told him the whole story. He got P0300 and P0302 first time. Then he did check the code one more time in the afternoon and got P0302. He switched the coil pack from 2 to 4 and then he agin got P0304 and then he told me that the coil-pack was not good. We put a new coil-pack and the car is runnign fine now.

I think the Toyota dealer ripped me off.

I thank you very much for you help and time. I remember you told me that the coil pack could be bad. But since the toyota dealer told me that he had checked it I thought they realy checked it but that was not the case.

Once again thank you very much.  

Answer
Apparently the "bozos" at the toyota dealer don't know how to look up service bulletins and how to check for an obvious engine misfire, I'm somewhat surprised at this, maybe you just happened to get an inexperience mechanic that was dealing with your problem or they just didn't take the time to check it, sorry you had this bad experience with this dealer, the technician you went to seems to know his stuff, I would go back to the dealer and talk to the service manager and ask him why their technician did not diagnose the problem correctly in the first place even after I gave you the information about the bulletin and ask to have some or all of the money you spend there needlessly to be refunded to you.