Xcobra
Diamond Member
Hey guys,
Haven't posted here in a while. So basically, I have been getting relatively bad mileage on my 99 Corolla (I have often used up almost 1/2 quarter tank on a 30-35 mile highway trip) for the past few months. I did a tune up when I bought it about a couple of years ago. I have also recently changed the oxygen sensors. I drive about 5K miles per year so I am confident it does not need another tune up. I do the oil changes at around 3K miles or 5 months given how little I drive it.
Last weekend, I took it to muffler place and basically told me that my bad mileage is due to broken/weak engine mounts (the two bottom ones, front and rear); he told me that basically the jerk from the engine when throttled allows some air to get in between the engine and the exhaust manifold thus using up more gas. In other words, he thinks it's a giant exhaust leak, triggering the O2 sensors to read the mix as lean. He revved it really hard a few times and when he did, there was a distinct noise coming out of the engine. I have also noticed this noise when I step on the gas to go up a hill, for example. It's almost as if you can hear the air leak, I guess? Given how much I have tried to troubleshoot this, this makes sense to me.
Now, I took it to another mechanic, said that the mounts were weak but not broken and quoted me for replacing the mounts at around $364 just for those two. This is getting on the expensive side for me. I can afford it but I am still hesitant. I have also wondered about replacing all of them if I will replace those two, thus probably driving the cost even higher.
Sorry about the long story, but what do you all think? Is it worth getting the mileage issue fixed by spending that much on something else?
Thanks for the help!
Update: I forgot to mention that I am more likely to believe the muffler guy's story because come emissions testing, it barely passes. Then again, I wanted to post here first before spending anything on this.
Haven't posted here in a while. So basically, I have been getting relatively bad mileage on my 99 Corolla (I have often used up almost 1/2 quarter tank on a 30-35 mile highway trip) for the past few months. I did a tune up when I bought it about a couple of years ago. I have also recently changed the oxygen sensors. I drive about 5K miles per year so I am confident it does not need another tune up. I do the oil changes at around 3K miles or 5 months given how little I drive it.
Last weekend, I took it to muffler place and basically told me that my bad mileage is due to broken/weak engine mounts (the two bottom ones, front and rear); he told me that basically the jerk from the engine when throttled allows some air to get in between the engine and the exhaust manifold thus using up more gas. In other words, he thinks it's a giant exhaust leak, triggering the O2 sensors to read the mix as lean. He revved it really hard a few times and when he did, there was a distinct noise coming out of the engine. I have also noticed this noise when I step on the gas to go up a hill, for example. It's almost as if you can hear the air leak, I guess? Given how much I have tried to troubleshoot this, this makes sense to me.
Now, I took it to another mechanic, said that the mounts were weak but not broken and quoted me for replacing the mounts at around $364 just for those two. This is getting on the expensive side for me. I can afford it but I am still hesitant. I have also wondered about replacing all of them if I will replace those two, thus probably driving the cost even higher.
Sorry about the long story, but what do you all think? Is it worth getting the mileage issue fixed by spending that much on something else?
Thanks for the help!
Update: I forgot to mention that I am more likely to believe the muffler guy's story because come emissions testing, it barely passes. Then again, I wanted to post here first before spending anything on this.
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