Hello and Thank you for reading first of all.. Ok well I bought this Fiero 86 SE V6 Auto 96K and the previous owner cut off the muffler and cat and ran a 2 foot section of flex pipe ..And I am wondering if that is the reason I have this enormous amount of fumes ..It is BAD BAD and the car runs like crap. It appears like the O2 sensor was replaced recently(the wire is somewhat white) I guess ..It is difficult to even work on the car with it running for a minute all garage doors up lol...My carbon monoxide detector goes off immediately after I start the car ..Has a rough Idle (sometimes) and when I stab the gas even the slightest it wants to die ..It is drivable but you have to ease into the throttle and has good power then....I am wondering what I should look into first ..Is most of it due to the rigged exhaust or are there any sensors I should try first? Thank you all!

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Jamie Mysliwy

[This message has been edited by jaydaug2008 (edited 08-02-2022).]

quote Originally posted by jaydaug2008: Has a rough Idle (sometimes) and when I stab the gas even the slightest it wants to die...

None of this has anything to do with a missing cat and/or muffler. Sounds like some basic tune up work needs to be done. First step would be to check for stored codes.

If you just got the car, you may find that the three spark plugs on the forward bank haven't been changed... for decades.

[This message has been edited by Patrick (edited 08-02-2022).]

Like above, new plugs, cap and rotor, plug wires will give you a great start.

Next you might want to replace the missing cat . I had some what the same on a ‘86 SE V6 where the previous owner put a straight pipe in place of the cat. I cut the pipe and installed a MagnaFlow #53004 High Flow cat from Summit. It was a 2” input/2” output cat. The new cat took the harshness out of the exhaust tone while used in conjunction with the stock muffler. Cost at the time was about $75. I was happy with the results. Also the MagnaFlow cat makes for an easy oil filter or starter change as the cat is quite a bit smaller than the OEM cat.

Though the cat might not buy you more time running your car in the garage, it might smell better. CO is still there and yeah it might make you sleepy.

https://www.summitracing.com/parts/mpe-53004

I agree that eventually installing a cat is the way to go... but make sure to get the engine running properly first. Otherwise the new cat will be poisoned and its life expectancy will be shortened.

[This message has been edited by Patrick (edited 08-03-2022).]

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[This message has been edited by Kevin87FieroGT (edited 08-03-2022).]