Couple issues that have me stumped...need help

[2GEffect6]

Okay I have a couple issues that need taken care of the first is when the car is idling it idles terrible it stumbles almost like its misfiring my downstream 02 is shot (dont know if that affects anything) also when i move forward or backwards slowly if i turn the wheel the car will stall sometimes or the rpms will drop way low and then jump back up real quick if it doesnt stall. it also stalls if i coast slowly and then hit the brakes hard. can anyone please help i want this running right so i can build it

 

[Talon IV]

Well the purpose of your lower O2 sensor is to just measure the catalyst's efficiency. If you are throwing a P0420 code, and you have high mileage, you could have a bad cat. possibly causing some of the issues you are having. Another great place to start checking is your Idle Air Control (IAC) valve. Im assuming when you are accelerating the car runs like it should?

 

[rlacasse1]

If the 98 is anything like the 95 n/t then you will have all sorts of jacked up issues if your downstream o2 sensor is bad. On my old 95 the car would barely run, the gas pedal was touchy as hell, and it would die out as well. Soon as i fixed the sensor, it ran perfect.

But, I would still do some more investigating before deciding it's your problem.

 

[2GEffect6]

Well the purpose of your lower O2 sensor is to just measure the catalyst's efficiency. If you are throwing a P0420 code, and you have high mileage, you could have a bad cat. possibly causing some of the issues you are having. Another great place to start checking is your Idle Air Control (IAC) valve. Im assuming when you are accelerating the car runs like it should?

yes it does run fine when i am accelerating i will replace the sensor and see what happens

 

[Smitherz]

Man this sounds kinda what happens with my 95 420a Eclipse. Runs good but just randomly stalls when you let the throttle fall back down to idle like at a stop light or shifting at low speed. I just did a full rebuild on the engine and I don't get any codes besides "the battery has been unhooked recently" code. I better order an 02.

Thanks rlacasse1 for pointing this possibility out.

 

[Aestabrook1]

This may be a dumb question but....i'm assuming its a standard transmission...stalling when you hit the break or stop??? do you know how to drive a standard?

 

[Smitherz]

Hah that made me laugh. When I went back and looked at my wording it does look like a newbie trying to learn how to drive. When I said stall I mean drop off the edge of a cliff like a covered wagon in the old west. In my case the rpm's just don't fall to idle and then turn off. I'm talking like someone turns off the key. It just dies instantly for no reason on decelerating sometimes. I got my new CPS in the mail yesterday and my new CAS should be here today so I'll update if those help my situation.

 

[Aestabrook1]

Ok, keep us posted

 

[2GEffect6]

This may be a dumb question but....i'm assuming its a standard transmission...stalling when you hit the break or stop??? do you know how to drive a standard?

its an automatic

 

[Guilty1s]

You know that little sensor on the top of the power steering pump that im sure everyone wonders what it does... well, it detects when there is a load on the power steering pump (aka turning) at idle, it increase your idle to compensate for the billion HP the PS pump takes to be used.

You can see it in this picture...

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and i also reallize once again that i answer a question about a N/T with a 4g in mind

Maybe the 420s have something similar too.