Not sure if I’m posting in the proper place, so feel free to move if I’m mistaken in my choice.
I took my truck in to Midas last year because my check engine light came on. At the time, they replaced the O2 sensor and the light went off, the truck ran great. About a week later, the check engine light came on again. I took it to a different Midas shop and they said that the muffler and several pipes needed replaced. Had all of that done, and then 3 months later, the muffler fell off and the check engine light came on again. Took it back to the 2nd Midas shop and they reattached it. This past Friday, the muffler became detached again. The check engine light came on, once again, and the power decreased. Whereas before the muffler was detached, I had no problems accelerating, I could now barely get the truck up to 20 mph. Took it back to the same Midas shop and they reattached it, but the check engine light stayed on, and, while the power is better than when the muffler was detached, I’m unable to accelerate to 55. I immediately took it back to Midas and was told that it’s a sign that the engine or the transmission has problems and that I need to take it to the dealership for them to run diagnostics on it. There’s no possible way it can be related to the exhaust system. I do have an appointment Monday to have diagnostics run on it, but have a strong feeling he’s not being exactly honest here. It seems too much of a coincidence for the muffler detaching, the engine light coming on, and the onset of the poor performance all happening simultaneously from different causes. Also, reattaching the muffler did improve the performance somewhat. Now I can go up to 50 mph where when it was unattached I could only go up to 20. Advice, please?
Well, past experience has told me that if your exhaust is not hooked up to the header outlet, and if your valves aren’t stainless steal, it can cause burnt valves and/or warping of the exhaust valves, causing low cylinder pressures, which means you can only go like 50 mph. …That’s just one example though. What kind of truck and year? Also, mufflers DO increase back pressure in the system therefore increasing performance.
All aside, I think you have issues elsewhere besides your exhaust IMO.
Amberlei, I had the same problem with my 89 Cavalier Z24. My muffler had several holes, and the tail pipe before the muffler had become seperated. It sounded cool for about an hour, then just got annoying, especially when it felt like I wasn’t getting up to speed. I changed the muffler and fixed the pipe, and added injector cleaner since as an impulse buy. The car picked up quite a bit for about a week, but after that, power dropped off a little. I don’t want to give cretit for the increase in power to the muffler and pipe repair alone, but I’m certain it helped. My car is old, 125k miles on it, and needs a few more things done to it. I suspect yours is the same. You treated a symptom, but haven’t cured the disease.
It’s a 92 Toyota pickup. It has 141K miles on it, and looks horrid, but has always ran well until now. I know this sounds really weird, but I’m very sentimentally attached to this truck. I’ll do anything I can to keep it running for as long as possible. I can’t seem to get mechanics to understand this. It’s been rolled off a cliff, long story there, but that’s been 4 years ago and it’s still ran fine since. I’ve driven it from Spokane to Boston, Boston to Greensboro, and Boston to Texas in it since. The body looks awful. I’m in the (long and expensive) process of rebuilding the body. New bumpers, driver quarter panel, door, bed, etc. Friends say I should just get a new truck, but I’m not ready to let this one go.
For proper evaluation of the check engine light (CEL) situation, you need a mechanic who knows what he’s doing. Top-flight mechanics are found at dealerships and the better independent shops, not at chain operations. It may not be so much a lack of honesty as a lack of competence.
Among the dozens (and in later cars, hundreds) of things that can turn on the CEL, it’s possible to get a code related to the O2 sensor from exhaust system leakage. The leakage can allow fresh air to to pollute (love the irony?) the normal exhaust gases that the sensor is designed to measure.
The muffler has come off twice since you had a new one installed? Something ain’t right there. May or may not be related to your other problems, but mufflers should last years, not months.
Not being able to get up to highway speed, and especially not above 20 mph, is a significant symptom, indicating a significant problem. Probably not caused by the exhaust system deteriorating, but very possibly related to it.
One possible scenario is the air leaking into the exhaust system caused the O2 sensor to give a lean (not enough fuel) reading, to which the “computer” responded by running more gas through the engine, which caused the catalytic converter to start plugging up and/or the spark plugs to foul, which can severely hamper power, and might have caused excessive moisture build-up in the exhaust pipes causing them to rust prematurely. That’s just a guess, but the point is that when the CEL comes on, there could be a lot more going on than just what one might infer from reading the trouble code that it sets. Make sure that whoever works on it next has expertise in drivability diagnosis and repair. Paying once for high-caliber work is usually less expensive in the long run than having partly knowledgeable folks fix just what is immediately obvious.
Don’t know what state you are in, but if you are required to have a catalytic converter these can become stopped up to the point that the engine will backfire and blow the exhaust off the car. (If you listen to your stereo as loud as I do, you may have missed the backfire) If the converter is stopped up, this can affect the performance of your car- may be a longshot but a definite possibility- and if so- the converter is part of your exhaust system and should you return to the same business the mechanic should agree to check it for free-
I’m in Massachusetts now. I think we have to have catalytic converters here. My truck passed the emissions test about 3 weeks ago. Don’t know if that has any bearing on anything or not.
I agree a muffler should’nt fall off but my experience is that a Midas muffler will last about a year and their exhaust pipes maybe a year and a half .
And the verdict is in. According to the dealership, it needs a new O2 filter (under warranty from Midas) and the clutch is starting to go. Now I’m really ticked at Midas because the least the guy could have done was to check for the cause of the check engine light, which would have told him that the problem was the 02 filter.