I want to get to the bottom of this ... why is my gas mileage BAD?!
05-02-12, 03:58 PM
#46
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Talked to my fellow mechanic over the phone and explained my situation.
He's pointing towards the sparks plugs saying "If the spark plugs are bad, then it'd be burning more gas"
I told him also that it could be a bad O2 sensor, but he told me not to worry about it if no CEL triggers towards it.
Is that true? He said he'll look into it so I'm going to visit him next Tuesday.
He's pointing towards the sparks plugs saying "If the spark plugs are bad, then it'd be burning more gas"
I told him also that it could be a bad O2 sensor, but he told me not to worry about it if no CEL triggers towards it.
Is that true? He said he'll look into it so I'm going to visit him next Tuesday.
05-08-12, 03:22 PM
#48
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Went to the mechanic today ... looks like my spark plugs are bad.
How much do they run around and what is the best brand out there?
I suppose this is the reason for the bad gas mpg?
How much do they run around and what is the best brand out there?
I suppose this is the reason for the bad gas mpg?
05-08-12, 04:52 PM
#49
Lexus Test Driver
Spark Plugs can be had for $50, get NGK Iridium or Denso Iridium, they are the same plug. Labor is going to expensive.
If the spark plugs are old, and aren't at full efficiency, then it can degrade fuel economy.
05-08-12, 05:49 PM
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So when he pulled out only one spark plug, he just assumed the rest were bad too. He wants me to get the high quality ones ... I believe he said the bosch platinum or something like that? Which lasts for 100-120k miles?
The mechanic is a good friend of my dad so he would do it for free ... but he said the rear would be a pain in the *** ... so he would do it on his off day from work at his house. He said something about taking out the whole intake manifold to get to the rear and that I have to buy a intake gasket or something like that too? Correct me if I'm wrong because he has a strong accent so I can't understand him all the time.
So yeah ... there you go. Spark plugs needs to be changed.
Oh, my mechanic mentioned while taking out the spark plugs - "From the looks of it, it seems like this car never had an engine tune up done before" ...
05-08-12, 06:05 PM
#51
Lexus Test Driver
He only checked one of the spark plug in the front and showed me it. Saying it was bad. From what I saw, it smelled, it was really dark, and looked burnt. This car has 178k miles and my Carfax report showed the spark plugs were changed at 130k miles. So does it make sense to go bad this quick?
So when he pulled out only one spark plug, he just assumed the rest were bad too. He wants me to get the high quality ones ... I believe he said the bosch platinum or something like that? Which lasts for 100-120k miles?
The mechanic is a good friend of my dad so he would do it for free ... but he said the rear would be a pain in the *** ... so he would do it on his off day from work at his house. He said something about taking out the whole intake manifold to get to the rear and that I have to buy a intake gasket or something like that too? Correct me if I'm wrong because he has a strong accent so I can't understand him all the time.
So yeah ... there you go. Spark plugs needs to be changed.
Oh, my mechanic mentioned while taking out the spark plugs - "From the looks of it, it seems like this car never had an engine tune up done before" ...
So when he pulled out only one spark plug, he just assumed the rest were bad too. He wants me to get the high quality ones ... I believe he said the bosch platinum or something like that? Which lasts for 100-120k miles?
The mechanic is a good friend of my dad so he would do it for free ... but he said the rear would be a pain in the *** ... so he would do it on his off day from work at his house. He said something about taking out the whole intake manifold to get to the rear and that I have to buy a intake gasket or something like that too? Correct me if I'm wrong because he has a strong accent so I can't understand him all the time.
So yeah ... there you go. Spark plugs needs to be changed.
Oh, my mechanic mentioned while taking out the spark plugs - "From the looks of it, it seems like this car never had an engine tune up done before" ...
And yes, he is correct, the rear are a pain in the ***.
Funny story: I did mine at my uncle's shop, and of course I didn't think and I started doing it one of the two lifts, and he lost a day's worth of business because the other lift was being used for an engine swap. Not to mention, that I screwed up and left a ground cable unconnected.
They generally don't go bad that quick, but it's possible that when they were changed at 130k, that they did not use iridium plugs like recommended. My plugs at 160k, didn't look that bad. Here's a picture of one of them:
EDIT: I just realized the picture look's like crap, but oh well you get the point.
05-08-12, 06:29 PM
#52
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Definitely, do NOT get BOSCH. Stick with OEM. Purchase the spark plugs yourself if you have to, and have him install them.
And yes, he is correct, the rear are a pain in the ***.
Funny story: I did mine at my uncle's shop, and of course I didn't think and I started doing it one of the two lifts, and he lost a day's worth of business because the other lift was being used for an engine swap. Not to mention, that I screwed up and left a ground cable unconnected.
They generally don't go bad that quick, but it's possible that when they were changed at 130k, that they did not use iridium plugs like recommended. My plugs at 160k, didn't look that bad. Here's a picture of one of them:
EDIT: I just realized the picture look's like crap, but oh well you get the point.
And yes, he is correct, the rear are a pain in the ***.
Funny story: I did mine at my uncle's shop, and of course I didn't think and I started doing it one of the two lifts, and he lost a day's worth of business because the other lift was being used for an engine swap. Not to mention, that I screwed up and left a ground cable unconnected.
They generally don't go bad that quick, but it's possible that when they were changed at 130k, that they did not use iridium plugs like recommended. My plugs at 160k, didn't look that bad. Here's a picture of one of them:
EDIT: I just realized the picture look's like crap, but oh well you get the point.
From looking at Advanced Auto Parts website, I can get each for $8 so not a bad deal. I'm willing to do it myself because it seems like my mechanic got scared once he saw how hard the rear ones are lol.
So HOPEFULLY this will be the conclusion of why I am getting bad gas mileage.
Also, wouldn't I have a CEL if my spark plugs were bad? Or is it only when they misfire?
05-08-12, 06:30 PM
#53
The Bosch plugs could be the answer to your fuel economy question. I have put those things in cars with worn out plugs and the new Bosch plugs made it run worse than the old used up ones. Like hypervish said OE only for plugs. If your mechanic's arms are not too short or too chunky, he should be able to get to the back bank without removing the upper intake.
05-09-12, 09:08 PM
#54
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Okay guys, good news!
I changed the spark plugs myself and I must say, I am never doing the rear ones again!!!! Such a pain in the ***, especially the far rear right one. No room to work with whatsoever!!
I bought NGK Iridium IX from Advance Auto Parts via http://shop.advanceautoparts.com/web...P|GRP2041_____
I got all six for $36 oppose to $56 because if you use this coupon RETMENOT123 ... you'll get $20 off. Trick is - you order online and use the coupon, then use the pick up at store option to the nearest store.
So instead of paying $56, I got it for $36.
Now back to the topic ... it took me about 2.5 hours. And engine seems to idle better and shift smoother. Gas mileage is now anywhere between 18-20 but thats because I was not hitting that many traffic lights today. I'll update you guys again when I start going back to work which is a 2 mile commute.
But now, I hear that I need a Intake Manifold gasket? What exactly is that? and do I need it? Can somebody please elaborate please? Thanks guys
Oh P.S. here is the picture of my old Denso spark plugs from the past owner. I suppose they're bad orrrr?
I changed the spark plugs myself and I must say, I am never doing the rear ones again!!!! Such a pain in the ***, especially the far rear right one. No room to work with whatsoever!!
I bought NGK Iridium IX from Advance Auto Parts via http://shop.advanceautoparts.com/web...P|GRP2041_____
I got all six for $36 oppose to $56 because if you use this coupon RETMENOT123 ... you'll get $20 off. Trick is - you order online and use the coupon, then use the pick up at store option to the nearest store.
So instead of paying $56, I got it for $36.
Now back to the topic ... it took me about 2.5 hours. And engine seems to idle better and shift smoother. Gas mileage is now anywhere between 18-20 but thats because I was not hitting that many traffic lights today. I'll update you guys again when I start going back to work which is a 2 mile commute.
But now, I hear that I need a Intake Manifold gasket? What exactly is that? and do I need it? Can somebody please elaborate please? Thanks guys
Oh P.S. here is the picture of my old Denso spark plugs from the past owner. I suppose they're bad orrrr?
Last edited by NyCrAzY; 05-09-12 at 09:13 PM.
05-10-12, 08:18 AM
#56
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I just removed the cover that contained the lexus logo and the 3allen wrench screws.
Also there was a lot of black sludge or something ( looked like crumbs of a brownie) around the oil cap.
Also there was a lot of black sludge or something ( looked like crumbs of a brownie) around the oil cap.
05-10-12, 11:08 AM
#58
More than likely the remnants of a gasket that used to be there to more or less "seal" that oil cap with the engine cover. The one on my ES300 is gone too...I'm not concerned about mine.
05-12-12, 07:34 PM
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Got 15mpg last tank in my RX, luckily me and my wife carpool now in my Camry. Only drive the RX for sunday errands and one day a week to work. The 34mpg my Camry gets is making me drive the RX less and less. Hasn't even hit 100k yet.