Help: Accord muffler causing Chitty-Chitty-Bang-Bang

Hello,

I recently replaced the muffler on my 95 Accord EX (4cylinder). Since then, it
runs very poorly. I'm trying to figure out if the muffler is to blame, or if
this poor performance is a coincidence.

Can anyone lend an opinion? Don't know if I should try to exchange the muffler
for a Honda-brand part, or if something else is going on.

TIA,
Kurt

Details:
================
I replaced the muffler with an "original replacement" unit from my local auto
parts store. I did not use one of the new "high performance" racing mufflers,
it is just a generic stock replacement.

Now when the engine runs a certain RPM's (say 1700 to 2500), it runs VERY rough,
like Chitty-Chitty-Bang-Bang. In fact, it shakes the car and rattles the muffler
all over the place. It only happens under "no acceleration", i.e. when I am
coasting at say 35-45MPH, with my foot lightly on the accelerator. Not speeding
up, and not slowing down... almost like it is quietly back firing.

This does NOT happen if the car is parked, in neutral. In that case, I can
rev the engine slowly through that RPM range no problem.

Could it be something due to different/incorrect back pressure from the new
generic muffler? My large V-twin motorcycle does the same thing (back firing)
if I ease off the accelerator and let the bike coast.

Let me know if you've heard of this type of situation before.
Thanks folks....

 

What kind of muffler did you get? If you tell me this, I can help you.
I've been down this road before...

Jonathan

 

What kind of muffler did you get? If you tell me this, I can help you.
I've been down this road before...

Jonathan

 

I'd try going to a muffler shop & getting a flow test on your cat-converter.
No mechanic here---just an idea.

 

I'd try going to a muffler shop & getting a flow test on your cat-converter.
No mechanic here---just an idea.

 

Oops...I actually read below the "===========" this time. ;-) I'd say the
only way to tell is to have a muffler shop check it out. It sounds like
either you do have WAY too much back pressure, or it is something else
causing the problem, and the timing of putting on a new muffler is just
coincidental. In any case, I'd go to a professional muffler shop and let
them check the back-pressure. Don't go to a shade-tree mechanic for this
one. Seek out a mechanic or go back to dealer only if the muffler shop
determines with 100% certainty that the muffler isn't causing the problem.

Jonathan

 

Oops...I actually read below the "===========" this time. ;-) I'd say the
only way to tell is to have a muffler shop check it out. It sounds like
either you do have WAY too much back pressure, or it is something else
causing the problem, and the timing of putting on a new muffler is just
coincidental. In any case, I'd go to a professional muffler shop and let
them check the back-pressure. Don't go to a shade-tree mechanic for this
one. Seek out a mechanic or go back to dealer only if the muffler shop
determines with 100% certainty that the muffler isn't causing the problem.

Jonathan

 

=================

We don't know the mileage, but if somebbody hammered the heck out of
your exhaust system, the catalytic converter could be blocking up at the
'in' side, because of crumbling, and plugging up flow.

Have you performed the 'lamp check' in the manual, to be sure your dash
indicators are working right? Sounds like you should be showing a CHECK
ENGINE for such bad backfiring.

'Curly'

 

=================

We don't know the mileage, but if somebbody hammered the heck out of
your exhaust system, the catalytic converter could be blocking up at the
'in' side, because of crumbling, and plugging up flow.

Have you performed the 'lamp check' in the manual, to be sure your dash
indicators are working right? Sounds like you should be showing a CHECK
ENGINE for such bad backfiring.

'Curly'