Spark Plug replacement

Nosmo King · 10-29-2008, 11:36 PM

I had spark plugs changed last year as recommended for my 60K mile service in my 2003 Prius. The parts supplier at my mechanic's recommended Iridium Autolite plugs.

Yesterday, my mass air sensor went out, and I took it to the dealer. He said that the autolite plugs were definitely not recommended, and suggested I pay for replacement (to the tune of $110.) Up until the mass air flow sensor went out, the car ran fine, and my mileage didn't drop after the autolite plugs were added.

I suspect I've been had, but I'm not sure by whom. Any ideas who is right?

Thanks.

Patrick Wong · 10-30-2008, 12:31 AM

The functioning of the mass airflow sensor will not be affected by the iridium spark plugs. I suggest that you have that component cleaned (or replaced if necessary), then see if any other problems exist.

In general, I suggest using the specified NGK or Denso iridium spark plugs to avoid the occasional P3191 engine does not start code. However if you don't have engine start or misfire problems, then no worries.

Nosmo King · 10-30-2008, 01:02 AM

Sorry, I didn't mean to suggest that the plugs were to blame for the sensor failure.

The autolite plugs were in the car for a year; over that time, no problems were apparent with misfiring or with gas mileage. Does that mean that the plugs should not have been replaced? Should I go back to the dealer and complain?

Thanks.

Patrick Wong · 10-30-2008, 10:09 AM

Toyota repair documentation and the Prius owner's manual recommend NGK or Denso iridium spark plugs. Therefore, your dealer service writer's assertion that Autolite brand plugs are not recommended is a true statement.

If your original complaint related to engine misfire or lack of power, the dealer mechanic may have replaced the spark plugs to rule out that area as an issue, prior to diagnosing the MAF as the problem. If you go back to complain, the service writer will probably say that you authorized the work to be done. Further, use of the correct plugs will probably prevent a future driveability problem.

Nosmo King · 10-30-2008, 11:17 AM

Thanks for the quick help.

10-29-2008, 11:36 PM	#1
Nosmo King Junior Member Join Date: Oct 2008 Location: High Point NC Posts: 3 My Car: 2003 Prius Model: Package: N/A Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Spark Plug replacement I had spark plugs changed last year as recommended for my 60K mile service in my 2003 Prius. The parts supplier at my mechanic's recommended Iridium Autolite plugs. Yesterday, my mass air sensor went out, and I took it to the dealer. He said that the autolite plugs were definitely not recommended, and suggested I pay for replacement (to the tune of $110.) Up until the mass air flow sensor went out, the car ran fine, and my mileage didn't drop after the autolite plugs were added. I suspect I've been had, but I'm not sure by whom. Any ideas who is right? Thanks.

10-30-2008, 12:31 AM	#2
Patrick Wong DIY Enthusiast Join Date: Mar 2008 Location: Green Valley, AZ Posts: 4,052 My Car: 2004 Prius Model: N/A Package: #9 Thanks: 21 Thanked 212 Times in 183 Posts Friends: 44	Re: Spark Plug replacement The functioning of the mass airflow sensor will not be affected by the iridium spark plugs. I suggest that you have that component cleaned (or replaced if necessary), then see if any other problems exist. In general, I suggest using the specified NGK or Denso iridium spark plugs to avoid the occasional P3191 engine does not start code. However if you don't have engine start or misfire problems, then no worries.

10-30-2008, 01:02 AM	#3
Nosmo King Junior Member Join Date: Oct 2008 Location: High Point NC Posts: 3 My Car: 2003 Prius Model: Package: N/A Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Spark Plug replacement Sorry, I didn't mean to suggest that the plugs were to blame for the sensor failure. The autolite plugs were in the car for a year; over that time, no problems were apparent with misfiring or with gas mileage. Does that mean that the plugs should not have been replaced? Should I go back to the dealer and complain? Thanks.

10-30-2008, 10:09 AM	#4
Patrick Wong DIY Enthusiast Join Date: Mar 2008 Location: Green Valley, AZ Posts: 4,052 My Car: 2004 Prius Model: N/A Package: #9 Thanks: 21 Thanked 212 Times in 183 Posts Friends: 44	Re: Spark Plug replacement Toyota repair documentation and the Prius owner's manual recommend NGK or Denso iridium spark plugs. Therefore, your dealer service writer's assertion that Autolite brand plugs are not recommended is a true statement. If your original complaint related to engine misfire or lack of power, the dealer mechanic may have replaced the spark plugs to rule out that area as an issue, prior to diagnosing the MAF as the problem. If you go back to complain, the service writer will probably say that you authorized the work to be done. Further, use of the correct plugs will probably prevent a future driveability problem. Last edited by Patrick Wong; 10-30-2008 at 12:24 PM.

10-30-2008, 11:17 AM	#5
Nosmo King Junior Member Join Date: Oct 2008 Location: High Point NC Posts: 3 My Car: 2003 Prius Model: Package: N/A Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: Spark Plug replacement Thanks for the quick help.

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