Thread: 500 RPM idle, running rich, missfire...

Bought a 99 GTP needed some work, replaced the rear o2, whole throttle body including sensors and the battery, no codes being thrown off, any ideas?
I have also noticed that when I put it in reverse and I get on it the lights also dim, could this be an alt problem? Would it cause all this?



Thank you!

Vac leak? Start spraying the lim with carb cleaner to see if the idle picks up

Why would you replace the rear o2? It does nothing.

Originally Posted by dsmuts

Why would you replace the rear o2? It does nothing.

Because one wire was torn up and it was throwing a code

Need a little more info. Are you getting front O2 and map signals?

I'm not sure how to check for that, I don't have any codes being thrown off since I replaced the rear o2.

Take a look at them on a scanner. Map should move as the throttle % changes. O2's should be bouncing up and down after 10 seconds or so of starting.

A low O2 reading means the heater isn't working and it's reading lean, so the pcm dumps fuel. Map not reading can also fudge up fueling pretty bad.

I did notice that it takes a while for it to warm up also when I accelerate the temp gauge reads that its getting colder.....

If you're coolant temp sensor is bad it'll run like crap. The motor will dump fuel because it thinks it's colder than it is

Gotcha... I will check that, where is it located?

Thank you, I will take a look at that

Use a real gauge that tells you your temp. Mine was acting up and telling the car it was -11* and the car ran bad and idled high.

Looks like a bad Tstat, and waterpump+ LIM are leaking