2000 Isuzu Trooper check engine light on, code P300, random

DSCHONEMANN

MEMBER
2000 ISUZU TROOPER
6 CYL
4WD
AUTOMATIC
95,000 MILES

Hi, I am a one owner trooper, last week my shop replaced the timing belt, wtr pump, all belts and spark plugs, the same day the check engine light started to flash and now it stays on. Everything was double checked at the shop including the plus, ND K16PR-P11 original plugs were installed, the only thing not replaced are the spark plug tubes, Code: P300 - random misfire on all, is what the scanner says. Hopefully someone can help. Thank you Dieter

6 Replies

IMPALASS

MECHANIC
3,112 POSTS

Hello -

To better assist you is your model the Limited, LS or S model? Also what is your engine size in liter?

Sometimes a cracked ignition coil can cause this. Check the coil for an cracks or any type of problem.......

Check to make sure the plugs are secure....... Why weren't the tubes replaced? Did you see them....... Do they look in good shape?

Take a spray bottle of water and start the engine..... While the engine is running mist water all over the plug wires and see if the engine stutters at all.

Check for any loose vacuum hoses... Cracked hoses etc.......

Low fuel pressure can also cause this......... Can you perform a fuel pressure check?

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Thursday, July 30th, 2009 AT 11:13 PM

DSCHONEMANN

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3 POSTS

The car runs just perfect, no loss of power, no rough idle, passed smog last month, after the repairs were done the check engine light came and stays on. Code P0300, random misfire on all cylinders is what the scanner is reading.

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Thursday, July 30th, 2009 AT 11:46 PM

IMPALASS

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Hello -

Thanks Dieter for the info....... Still a couple of other questions above I needed answered. Here they are again just in case.

To better assist you is your model the Limited, LS or S model? Also what is your engine size in liter?

Sometimes a cracked ignition coil can cause this or low fuel pressure. It has to be something common to all of the plugs.

For now since the car is running just fine, take it to Auto Zone (AZ) or O'Reilly's (OR) and for FREE they can pull the codes to the car. We know it is code P0300 but I just want them to clear all the codes for now. Then just drive it as normal.

There are times the car will throw a code and it can be the computer blinked for a second, the fuel pump maybe dropped slightly in pressure.....A number of things. If the car is running just fine, then I normally make note of the codes and clear them and drive normal. Then if it throws them again now you may have a problem. But if all is okay I wouldn't worry right now.

Now you do have 95000 on the car so keep the fuel pump in mind for the future. Also, at 75000 your timing belt was to be changed. Please keep that in mind as that could damage the engine if it breaks.....

Keep me posted

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Sunday, August 2nd, 2009 AT 12:37 AM

DSCHONEMANN

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Thank you for your reply, yes it is a Trooper LS 2000, 3.5L; the timing belt, wtr. Pump, air cleaner and spark plugs were replaced, K16PR-P11 (original plugs) actually after the repairs were done the "check engine" light came on and the shop double checked everything. I don't think they did anything wrong, somehow something got disturbed. I will replace the fuel filter next. Dieter

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Monday, August 3rd, 2009 AT 12:28 PM

IMPALASS

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Hello -

Thanks again for the updated info.........I agree.......I don't think they did anything wrong either.

Many times as I said, just like the power in your house will surge or blink..... That kicks the clocks out, reboots the computer etc......... Same with the cars. Just the slightest drop in voltage could have caused a delay and the PCM kick out the code. That is why I suggest since the car is running good for now, clear the codes and drive it and see if it happens again.