Laurance

Hi all,

I have a 2002 LS430 which is just coming up to 300,000 miles.

I had it converted to run on propane around 150,000 miles ago. I have been using an upper cylinder lubrication system but this was not working for around 30,000 miles, on and off.

Recently I started getting a flashing Engine Light along with a P0301 code (mis-fire on cyl 1). This would happen ONLY when the engine was completely cold AND under load - eg. pulling uphill at low revs. Any combination of flat/downhill terrain AND/OR engine warmup and the "fault" would clear.

As the weeks have gone on (I do around 1,000 miles per week) it has got worse; ie. "fault" is more easily precipitated and takes longer to clear AND can sometimes appear WITH a warm engine under load (only very occasionally).

I monitor the fuel consumption quite carefully and I am not seeing any significant increase.

The physical "mis-fire" sensation is only noticeable when stationary, in drive, at idle. To give an idea, on a scale of "1 > 10", if removing the coil lead for 1 cylinder was a "10", then this feeling is around "3 or 4".

I should clarify that although the flashing engine light and P0301 codes are only occasional, the feeling of mis-firing is constant.

There are no other codes.

Around 50,000 miles ago I had a very strange problem with misfire codes on most of the cylinders in No. 1's bank. This would happen on gasoline BUT not on propane and completely cleared up following change of spark plugs and air filter and has been fine ever since.

The present problem is the same whether running on gasoline or propane - each system has it's own dedicated injectors.

So far I have swapped the cyl 1 ignition coil with it's neighbor to rule that out AND I have replaced the cyl 1 spark plug - no difference.

I'm not sure what could be the problem OR what I can try next.

Any ideas would be gratefully received.

Kind regards,

Mike

P0301 means "Cylinder 1 Misfire Detected"

Possible causes

- Faulty spark plug 1

- Faulty ignition coil 1

- Ignition coil 1 harness is open or shorted

- Ignition coil 1 poor electrical connection

- Clogged or faulty fuel injector 1

- Injector 1 harness is open or shorted

- Injector 1 poor electrical connection

- Improper spark plug 1

- Insufficient cylinder 1 compression

- Incorrect fuel pressure

- Intake air leak

learn more at: http://www.uobd2.com/upload/service/diagnostic-trouble-code-table.pdf

Symptoms:

-Engine Light ON (or Service Engine Soon Warning Light)

- Lack/loss of power

- Hard start

- Engine hesitation

Hi, dear,

I notice you post a link: http://www.uobd2.com/wholesale/mini-vci-for-toyota-tis-techstream-v500028-1888.html

do you mean you bought Techstream from here?

but as I know users are not allowed to buy an additional cable to use, otherwise this Toyota techstream will not work, and techstream only works as tester not programmer.

Good luck!