Poor gas mileage since repair- thoughts?

[thewizard16]

Hey all,

I had the gaskets, several seals, the water pump, and the timing belt along with the tensioner and whatever else goes into that job, replaced on the V6 Camry about four months ago and since then it's been getting about 20-25% lower gas mileage and doesn't seem to have quite as much power as it did before. I ignored it for a while and assumed if might just be a temporary side effect of relatively significant work, but now, quite some time afterwards, it's still getting the same low gas mileage and still seeming off on acceleration. For those of you more familiar with this sort of thing than I, what could cause this? The problem seems too tied to the repair to be a coincidence or new problem (which I'm sure a less reputable shop would try to convince me of), so what should I be expecting to contribute to this, and what should I ask the repair shop when I take the car back in shortly to have this issue looked at? I'd have had it taken care of sooner but I've not been in town much recently and I'd hoped it was something that would work itself out (ignorant, I know) so I have to deal with it now. Thanks in advance for your input.

[JWC]

This something you should have gone back to the dealer about immediately. Either a vacuum line is mis-routed or they have the timing off...which could mean taking it back apart.    After that much time, they will probably charge for the repair or check.  I wouldn't even go back to the same place now, until after I have been elsewhere and confirmed what the problem is and related to.  If it is related to the timing belt replacement, you have more information to convince them to stand behind the repair.

[Eye of the Tiger]

I vote for the timing is off. That sucks.

[thewizard16]

Thanks for the input guys. I spoke to a legitimate mechanic friend today and he had the same opinion, but unfortunately he isn't local so it's still just an opinion from the description I gave of the issue.

This something you should have gone back to the dealer about immediately. Either a vacuum line is mis-routed or they have the timing off...which could mean taking it back apart.    After that much time, they will probably charge for the repair or check.  I wouldn't even go back to the same place now, until after I have been elsewhere and confirmed what the problem is and related to.  If it is related to the timing belt replacement, you have more information to convince them to stand behind the repair.

Thanks for the advice. Unfortunately it is not the kind of problem I noticed immediately, nor would I expect most people to, honestly. The loss of power isn't severe, it is only noticeable under hard acceleration, which I don't do on a daily basis since 98% of my driving is city driving anymore, or when climbing hills and even then I wasn't sure there was a real loss of power at first. The mileage issue also wasn't detectable for a few weeks since I didn't fill up for a bit after the repair and it was only a half tank anyway (I was on vacation for a week right after the repair and the car didn't move, so first fill up would have been at least two weeks after the repair). I noticed the mileage drop on the first full fill up, but I had not detected the power malaise yet so I chalked it up to any number of hypothetical things. I was then out of town for two months (with the car, which is when I figured out that the mileage drop wasn't improving and first noticed it was having to work harder on hills and couldn't get up and go quite like normal) so I've really only been back in town and couple weeks and this week have finally been catching up with things on the to-do list. So as weird as it sounds, this is actually about as quickly as I could have had anything done about it with the original shop by the time I knew there was actually something a little off. I don't think it's a vacuum hose being misrouted and I've gone through and checked things I could see/think might affect it, but the symptoms of a timing belt being off a notch line up a bit too perfectly with what's going on. I think I initially rationalized that if the timing was off the effects would be more serious/noticeable, but that was probably defensive reasoning since I didn't want to have to drop a bunch of money fixing something else. We'll see, I guess.

The shop has a 12 month warranty on all parts and service so I don't feel it's worth the money or time go somewhere else first for back up on my opinion. I wouldn't have had work that expensive done at a place that didn't have a good reputation and at least some warranty, so I will certainly give them the chance to recognize and fix the problem under warranty first before I contemplate other options. If they balk and try to come up with some excuse that I may have done to drop the mileage, etc. then I'll worry about forcing them to stand behind their work, but they were very upfront and fair with me so far and they have a strong reputation among several friends that drive much nicer vehicles than I do, so I'm optimistic.

[thewizard16]

In the shop now- timing cover was removed and belt examined- they said the timing was spot on. No problems with the vacuum system. They said they adjusted the distributor "4 degrees" but saw no problems otherwise that they believe would be causing my power/mileage issues. So.... now I'm a bit at a loss. Thoughts?

[Eye of the Tiger]

Check all the wiring to make sure there are no loose connections?
It could also have nothing to do with having the timing belt replaced, like maybe the spark plugs are gone. Just a shot in the dark. It's hard to say from way over here. 

[thewizard16]

It's not misfiring or anything, which is why the mechanic didn't notice any problem when he drove it. I told him it might be difficult to notice if you hadn't driven the car day in and out for a long time, but flooring it on an onramp or trying to accelerate/maintain speed without downshifting going uphill would be the easiest way to notice the power loss, but only if you could compare it to before.

Here is what was replaces in April:
Timing Belt/cover/tensioner assembly
Cam seal
Water pump
Valve cover gasket
Oil seal
EGR gasket
Plenum gasket
V belt
Spark plugs
Distributor assembly

The wires were replaced three years ago. It shouldn't be the wires, it's not misfiring/causing a code, and the spark plugs are all new. It's annoying to know there's an issue but not be sure where to even tell the mechanics to look at this point.

[thewizard16]

Update- after the "distributor" was corrected, the power issue seems to have resolved. He said that the computer can correct for it being off like that, but it might err on the side of caution to avoid a misfire and cause the power malaise I was noticing. I haven't checked mileage yet, so we'll see if that had anything to do with it, but I'm hoping it was something that simple to fix. Unfortunately now they've noticed a rear wheel hub is going to need replaced and it turns out those suckers on this car are expensive. Oh well, it's always something.

[S204STi]

Well, if the base timing is off no amount of computer correction will give you proper power.  Glad it wasn't anything major.