ive searched and found a few things but none has worked for me the issue im having is when i first start the car the rpm jumps up and down for the first few seconds than idles at anywhere from 1-2k some and when im driving it wont drop between shifts and when im coming to a stop in neutral it will stay at a high rmp till i come to a complete stop where it will go back to the weird idle again

o and like the title says it runs rich rich enough to where i can smell it some times and when i floor it it will blow some black smoke

mine is practically doing the same thing and ive tried everything for mine if you have a cold air intake on your car try taking it off and putting the stock one back on mine use to this as well. but mine would load up the pistons as i was coming to a stop and would shut it off after i had stopped. it does idle a bit weird still now that i took my cold air intake off like it will idle up and down sometimes while im stopped but it actually runs fine besides when im stopped if you have any other ideas to what it could be help me out and ill try to help you out

Are you getting check engine light displayed? I would check ur 02 sensors are working correctly and your Cat converter isn't plugged.
Good luck.

Make sure your IAT sensor is plugged in.


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

i changed everything o2 sensors, IAC valve, throttle positioning sensor, new cat, crank sensor, cleaned throttle body, and had it put on 5 different computer at 5 different garages its not throwing anything also put a new fuel filter and injector cleaner and MAP sensor, nothing has worked will and air temp sensor cause the car to idle rough and shut off at random times?

i do have a cold air intake and i dont have a cat anymore or the rear sensor it hasnt had the 2 since i bought it and it ran just fine b4 all this has just started over the past few months and i have owned the car for 5 years

if you just put the cold air on right before it started acting up try putting the stock one back on mine pretty much stopped after i took mine off i know that some cars are wired like that if there not tuned for it but i dont know honestly. mine pretty much just doesnt when its cold once its warm im good so im not to worried about it now but its going to another garage to see if he can find anything ill let you know soon as i figure something out and if you figure something out before i get back to you let me know

the cai was on for a long time now and was working fine with it b4 im going to redo my grounds because i notice that if i scan the car when its running @!#$ty it will have a bunch of sensors reading low voltage so im pry going to do that tonight or tomorrow ill let u know what happens

I am having close to the same problem, have you tried unpluging the air charge temp sensor to see how it runs?

What causes the black smoke, could that be from simply too much fuel, or could it be antifreeze?
If it's getting too much fuel for the amount of air it gets, isn't the fuel pressure regulator returning plenty of gas back to the tank?
Are the spark plugs not burning enough of the mixture?

i have no clue what is causing it to run rich i dont even know where to start with that one im just trying to get the rpm thing figured out who knows if i fix one it might fix the other

well since im on here i might as well ask what u guys would do to try and figure out whats going on with the running rich thing

My 96 z24 is running rough and really rich i got codes 141 and 325 which i think are o2 and knock sensor, correct me if im wrong plz!! I was told by a really respected mechanic that if i change those it should fix both problems

had the same problem last week, change your 02 sensor man, its dumping so much fuel that it cant keep up causing the extra smoke out the back, its unburned gas.



2010 Lonestar Bash 2nd place J-Body Street Class
2011 texas heatwave 2nd place american compact street class

pull the o2 heater fuse see if check engine light goes off/ stays off didnt help the running rich but smoothed out my idle

i still never figured mine out. if i let it sit to long it almost loads up with to much gas and floods itself out. i have no clue what it could be but what i do know is that it is running rich if someone would have an idea to what would cause it to load up with gas please help.