80 running rough after Cat delete (3 Viewers)

[offroadvegan]

Hello!

Just picked up the LC after getting the CDL fixed as well as the cat removed. I was looking forward to a smooth ride home, but it feels like it is misfiring, or at least running rough. Toyocom shows switching from lean to rich alot. The short o2 has been replaced with a new OEM, the other is in place but is original.

No other changes to the vehicle. No CEL.

Could it be a backpressure change? Should I have the ECU relearn with no cats?

Any help is appreciated.

Scott

 

[ceylonfj40nut]

Check original O2 sensor just to make sure.

 

[fz1boxer]

Replace the other O2 sensor

 

[offroadvegan]

Replace the other O2 sensor

On backorder from wits end

 

[offroadvegan]

Replace the other O2 sensor

And wouldnt that throw a code or at least CEL?

 

[Railwelder93]

Have you tried disconnecting the battery for a while and then taking it for a drive?
After reconnecting the battery obviously

 

[offroadvegan]

Have you tried disconnecting the battery for a while and then taking it for a drive?
After reconnecting the battery obviously

Lol yes. Disco'd the neg, and let it sit for 30 mins. Then idled it in the drive. Still rough.

 

[Railwelder93]

Lol yes. Disco'd the neg, and let it sit for 30 mins. Then idled it in the drive. Still rough.

Gotcha.

 

[offroadvegan]

Gotcha.

My gut says it doesnt like the exhaust. If the other o2 was bad it would throw a code right?

 

[ajax1]

Did you put in a ntk sensor?

 

[Irish Reiver]

What year?

 

[Rwhat]

Disconnect the positive AND negative and touch the cables together.

 

[Railwelder93]

Yea, what year is your truck?

 

[offroadvegan]

Did you put in a ntk sensor?

Yes. From wits end.

 

[offroadvegan]

Yea, what year is your truck?

1993

 

[Irish Reiver]

Have you checked that both sensors are toggling Lean / rich on your toyocom.

 

[Railwelder93]

I can’t think of any reason why it would not run without the cat. I’d definitely replace the old sensor so you have 2 new.

And also check unrelated stuff, wire harness at the firewall/ vacuum leaks, and so on. It’s possible that something was disturbed when the work was done that has nothing to do with the exhaust.

 

[retrofive]

If like said the battery was disconnected, how many miles have you put on it since? The ECU goes through a learn cycle. Stop and start cycles and hwy speeds. Mine always ran like crap for about a week for it to relearn.

 

[baldilocks]

Why did you remove the cats anyway????

 

[offroadvegan]

Why did you remove the cats anyway????

Shop broke a stud replacing O2s and the angle was tough to resolve. They were original, and I had no prior history and wasn't sure how the flow was. So I told him to cut out the old exhaust, and just replaced it all.