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suraj

Check Engine Light After Delay In Oil Change...

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Hi guys,

First of all, oil change was not overdue, it was right on 5000 miles mark.

I noticed some power loss when I pressed gas so thought may need oil change soon.

Then all of a sudden after driving 20 miles, check engine light came on.

Took it for an oil change, power felt a lot better than before but check engine light is still on.

Not sure what's wrong. I'll take it to an autozone and have them scan.

Is it just a maintenance schedule triggering the light or something else messed up?

Thanks for any ideas if you had similar problem before.

--

Suraj

2000 RX-300 2WH

91K miles

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<_<

There should be no relationship between changing your oil and increased power. Either the keyword here is "felt" or the problem had temporarily abated.

The symptoms you describe (loss of power, Check Engine light) can easily be caused by the loss of a cylinder. In my case (both times) it was an ignition coil failure. If it is an ignition coil, the next symptom will be the transmission will not shift into overdrive. This symptom will usually move you in the direction of a qualified mechanic. Your Lexus dealer or a qualified independent mechanic will have the diagnostic equipment to determine if a coil (or possibly a fuel injector) is causing the problem. A simple OBDII scanner may not return enough information to point directly at the problem. Coil replacement by a dealer will probably run in the neighborhood of $400. Ask me how I know. That said, if you are reasonably handy with a wrench, changing out a coil - especially one of the front cylinders - is a fairly easy DIY>

Let us know what you find out is causing the problem.

Lotsa luck.

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Took the car to Autozone and it came up with PO171 code and had 4 possible causes:

1. Vaccum hose or something leaking

2. MAF sensor

3. ECT or CTI (not sure)

4. O2 sensor

The guy there suggested to check hoses for any leaks or if they are loose.

Bad thing is it cost as much to diagnose as to fix. :(

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Took the car to Autozone and it came up with PO171 code and had 4 possible causes:

1. Vaccum hose or something leaking

2. MAF sensor

3. ECT or CTI (not sure)

4. O2 sensor

The guy there suggested to check hoses for any leaks or if they are loose.

Bad thing is it cost as much to diagnose as to fix. :(

The attached file explains how to troubleshoot some of those issues. Good luck!

SFI__SF__file.pdf

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Thank you Joe for the pdf.

But since I'm not a DIY guy, the only thing I can do before taking to a mechanic is to check hoses.

BTW, how often the spark plugs need to be replaced? I have 91K miles and I heard Lexus recommends replacing them at 100k.

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Thank you Joe for the pdf.

But since I'm not a DIY guy, the only thing I can do before taking to a mechanic is to check hoses.

BTW, how often the spark plugs need to be replaced? I have 91K miles and I heard Lexus recommends replacing them at 100k.

I would check the owner's manual for that info. Mine were changed at 100K. Not sure of the specs. Good luck.

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Well, I checked the hoses that I could and can't tell if anything is loose or broken.

Do you think this (PO171) can be fixed by local mechanic or is it serious enough for a dealership work?

Dealership is pretty expensive.

I read some other posts and will try adding a fuel system cleaner to see if that helps.

I'll take it for repair this weekend.

BTW, how hard is it to clean MAF? If there are detailed steps, I can try that.

Thanks

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Thank you Carguy for the link.

Anywho, I went to Autozone to try the cheapest troubleshooting step first and got this Techron fuel system cleaner: http://www.autozone.com/autozone/catalog/a...questid=1197047

Then went to a Shell gas station, put the Techron in and filled tank with highest octane premium gasoline.

Removed -ve terminal from battery to reset codes.

Next morning, I hooked the battery back up and drove around pressing gas to get high rpms...

So far, I have driven around 70 miles after that and the CEL has not come back yet. Hope this continues on.

:)

If it comes back :(, MAF cleaning would be next step.

Thank you

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