Hello,

My friend drove like 200 miles while he had a really bad misfire on his 4th cylinder due to a bad distributor and damaged his catalytic converter. Towards the end of the drive his truck was sputtering as hell and it felt like he was driving against a hurricane.

But anyways, the distributor was replaced and the misfire vanished but the truck still ran like absolute crap. His mechanic friend took a look at it and said there was so much backpressure it was like the truck was being choked. He drove it without the o2s and it ran fine. Conclusion = bad cat. So they cut the main cat out and hollowed out the smaller pre-cat. Currently there's a leaky flex pipe installed where the main cat was.

Since he lives in CA a replacement cat is upwards of $1000. Considering that's 1/3 of what he paid for the truck he doesn't see himself spending that much $. As far as he can tell he has three options:

1) shell out ~$1000 for a whole replacement 'y' system that includes both cats.

2) have a shop weld a proper straight pipe until he can afford a ~$1000 'y' pipe or option 3 pipe.

3) buy an aftermarket cat like a Magnaflow ($300) and put it where the main cat was. His question regarding this option is this: since the pre-cat is hollow now, will his truck pass emissions with just a single aftermarket cat installed?

What would be the better of the three options? He would drive around how it is right now but the flex pipe really is leaky and he doesn't feel like it's a proper repair. It's neither here nor there.

Thank you

 

First off, a shop cannot legally weld a straight pipe in place of a catalytic converter. As a starting point for your friend, he should call around to some other shops to check prices. Last year (2020), I had my cat replaced on my 2000 S-10 4x4 by a muffler shop. They charged me $150 for an aftermarket cat and $80 for labor. Seems to flow great but I've never actually checked using backpressure tester.