I have a 240sx that I put a ls1 in.
Car has ms4 cam .675 prc valve springs.
Bbk intake and throttle body.
Sikky long tubes.
And the car has a Texas speed and performance tune in it.
Car ran great for the longest time.
Has 3"with x pipe and vibrant performance race mufflers.
Well, when I had the exhaust ran I bought header buddies to connect the headers to the exhaust and the exhaust shop welded them to my headers and somewhat tightened the header buddies.
I was unaware they barely tightened them and drive the car one day and got about 20 miles from home when the bolts fell out on the drivers side and the exhaust came unhooked from t the header.
So the car began running like pure **** but I had to drive home to fix it.
So I drove home, bought some new bolts, and reconnected the exhaust.
Took the car up the road only to find out that it runs extremely rich and runs like pure **** still. Can't seem to find the problem.
After the car warms up and you sit still the car idles at like 2000rpms till you sit completely still for about 5 seconds.
All help would be much appreciated.
Thanks.

 

You may have fouled the front o2 sensors when the exhaust came off. Is the SES light on ? You might have to replace the front o2's.

 

No check engine light.
And I thought so too so I bought some ceramic sensor cleaner and tried cleaning them but it still runs like crap.
I know the check engine light works cause when I did the cam swap it kept throwing P0106 (rough idle)
But I ordered new Bosch O2 sensors but they won't be here till Wednesday.
I appreciate your help.
Makes me feel better about the issue.
But don't I have to reset the pcm after I install the new O2's?

 

And when I cleaned them they was covered in black. Real thick.

 

Yea id put some new 02s and see what that does

 

A lot of people F-up their o2's when they run open headers because the cooler fresh air can hit the o2 and give it a false reading. The fresh air makes the computer think it's running lean and then it dumps fuel to compensate and well... Fouled black o2's. You might want to think about changing your spark plugs if the o2's were that black.

Also I would go back and give that exhaust shop a piece of my mind.

 

I changed them once cause I thought maybe they got fouled out from running one open header but it still ran bad and rich. I'm going to change them again once I change my O2's out.

 

Hopefully the plugs and the o2's will get you fixed up.

 

thanks everyone.
i will let you guys know the outcome once i swap everything out.

 

I think I may have found my problem. Not so sure yet. I have replaced my o2 sensors and have a new set of msd wires and ngktr55 spark plugs on the way. There's a thread on this forum with a link to buy new ms d wires which comes with 8 spark plugs for $70 with free shipping so if anyone needs any, buy them now. I'll let everyone know if this gives my issues when they arrive. I appreciate all input I've received as you all have been a great help. I'm a member on multiple forums and this is by far the most friendly forum. Thanks again.

 

How does it run in open loop?

 

Well, for the short period of time I was running open loop, it ran like straight S**T. Rich as hell and torqueless.

 

You sure you don't have a stuck open injector?