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2001 Toyota Tacoma - Why do I need a muffler

Why can’t you get a vehicle inspected without a muffler?

You need to explain your question. Like what type of inspection?
On the other hand, why haven’t you had your exhaust system repaired?

Because the inspectors don’t want the loud noise of your unmuffled vehicle in their facility?

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Pennsylvania requires a complete exhaust system, leak free as close to original manufacture as practical. Excess noise with a straight pipe or CO with a missing muffler are the major reasons for this. Also the muffler is part of a tuned system providing the correct back pressure to the engine. With out the proper back pressure bad things can happen like burned valves and excess pollution.

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A straight pipe won’t cause burned valves or excess pollution (with the converter in place). Other than excess noise pollution.

Some cities/states have noise ordinances.

Tester

In my county you can. The only requirement is that the exhaust pipe exit behind the passenger compartment, though apparently side exit exhausts seem to be fine as well. I had Bronco with a custom straight pipe exhaust for years. It passed inspection just fine…even without cats or mufflers.

No offense, but a Taco doesn’t exactly have beefy exhaust note.

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That’s mostly just an old wive’s tale, particularly when you’re talking about 20 year old vehicles. You’re not going to burn a valve with a straight pipe and if you leave the cats in place, you’re not going to effect back pressure significantly nor are you going created excess pollution. If you remove the cat(s) you certainly will though.

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No it doesn’t. My old 99 Taco had the cat removed when I bought it, but the muffler still in place. Then one of the welds failed on the pipe they welded in to replace the cat. So the Taco ran the near equivalent of open headers for a few days before I got it repaired. It didn’t sound great. But it was fun for a few days, in a comical sort of way.

3 years ago the county’s (Bernalillo, NM) inspector failed my '87 Toyota pickup because there were too many holes in the muffler. I resent having to hear the cars that lack them.