2000 ZX2 MTX Stall in neutral and rough idle...

Ok here we go, Bought the car a month ago. The car after about a week began to stall coming while coasting to a stop. Only mod on car is a typhoon intake and catback exhaust at this point. Its a 2000 MTX ZX2, i noticed that the previous owner had done the a/c quick fix to bypass the ccrm. I had no idea what they had put the wire there at the time. I pulled the wire giong from the low pressure a/c switch to the a/c compressor. A/C died and horn died. Went to Pep Boys and after 4 hrs the tech says its the IAT. I replaced the IAT/MAF, then he said its the computer. Replaced the computer with a brand new one from dealer and then with a s/r pcm XHG3 i think. Right before IAT car wouldnt even hold an idle. After IAT car could hold an idle a little better. Now car would still stall coming to a stop but it could idle at the very least. Also that day RPM’s started shooting up to 3k just by moving car a little. When at complete stop after a couple of seconds the rpms would drop back down to 800 to 1k rpm. If i did a WOT and let off the engine would struggle to idle and stall. Next day car threw code O2 sensor. Changed the O2 sensor on mani. Car stopped shooting up on rpm’s. Car still stalls, and has a rough idle. Then i noticed that it doesnt just stall while coming to stop but just by coasting in neutral. Usually when i coast around 50 mph for the most part just by either pressing the clutch pedal to neutral or pulling out gear into neutral the car’s rpm’s will begin to drop then try to go back up and just die. I just bump start it back up or turn key and car turns right back over no problems. Also noticed that sometimes in neutral rpms go back and forth between 750 to 1k rpms over and over. Car sounds like if its growling. Then after just stabbing in the dark and changing some possible parts that might be causing problem i change. The IAC, TPS, spark plugs, and something else. When i step on the brakes the lights dim. Replaced batter after it sparked and killed some fuses and alternator. So i replaced the alternator also. I use the votlmeter on my radar to check the voltages. Before i would get 14.0v now with new battery and alternator i get 14.4 or 14.5v. All of a sudden ill see my lights dim back and forth. Volts drop to 13.8 and back up. Light flickers at 6.5k rpm had alternator checked off engine and on charging is good and battery is good. Stalling was occuring before the all this but thought id mention it. Also one day clutch got sticky and couldnt shift. Slave cylinder line cracked and shot brake fluid out and no pressure. Replaced slave cylinder, master cylinder, and line. Replaced the blown fuses also. Just wondering what the heck is going on and why could my car be stalling and rough idle. I cant coast and its getting really annoying. Could it be timing belt? Checked serpentine and still good. BTW changed pcv and fuel filter.

Right now its with a mechanic/elictrical guy whos working on a/c. I’ve been told its a vacuum leak and therefore I told this mechanic to check for a vac leak and so far he’s told me there is none. If im idle’ing and give it a WOT to hear intake the cars idle goes crazy low, and even stalls sometimes. I’ve read that the use of 10w-30 oil could cause a rough idle and only 5w30 should be used. I don’t know what oil it has in there at the moment. What’s the spark gap supposed to be at? I bought some motocraft platinums and i think their pre-gapped at .050. Ive changed the pcv filter also. Thanks.
Any suggestions welcome. Thanks.

5W30 MUST BE USED . If your getting a check engine light , scan for codes. To me it just sounds like the first o2 sencor mounted in the pipe just after the exhaust manifold. But it could also be the throttle position sencor or even the throttle cable , or even the butterfly in the throttle body itself . Considering you didnt but it new it could be anything , have a trusted mechanic look at it . I’m sorry this is happening to you , I’ve never had that much trouble with my zx2 .

I don’t know what oil the dealer who sold it to me put in. So tomorrow im putting some 5w-30 in. Should i put seafoam in the oil before changing it? No codes being thrown. Should i just change the pipe o2 sensor anyways? Also had another mechanic check for vacuum leaks today, says there are none. Thanks.

Car finally threw another code. Im thinking its the O2 sensor on the pipe. Like ZXTUNERINNY mentioned. P0171.


Well went to autozone and they couldnt find the other sensor for water temp. But i changed the switch, oil with 5w30, did coolant flush, new temp switch, new thermostat. And things are the exact same. The moment i plugged that thing back in i stalled by the first corner i coasted too. As soon as i unplug fans come on and it throws a code dont know it cus i erased it but it came back so ill post it tomorrow. But when it has code i guess it jumps into limp mode. Can fell power loss thats why i say that. But car will not stall at all while coasting. And with temp switch plugged in and turn off car and back on the car immediately struggles to hold idle. Does this mean theres a short somewhere? Can the ccrm be causing this since a/c is also gone? Should i swap out the coolant temp sensor too? Thanks.

Heres another idea that I dont think you’ve tried yet. check your throttle body. I know you said you replaced the TPS, but maybe the Throttle Body gasket is cracked and leaking air into the intake? or maybe your idle air bypass is plugged / cracked on the inside of the TB? You may even want to check the whole intake system. (intake, TB, manifold). It sounds like thats about the only thing you have NOT tried yet.

K I will check those but first I’m replacing ccrm I think previous owner might have fried it. When they did ac fix. If no better taking intake system apart with tb. If not then checking valves. It squirs oil out when I take oil cap off and car running unless supposed to be that way.

Ok just replaced the CCRM, car ran great for 6 minutes then $((# it started stalling and idle went to crap again. I did notice that when i let it reset through neg cable for about 10 minutes it will run just fine for about 10 minutes then go back to running like (*#$. But if I unplug the temp switch and leave it off car will go into limp mode i think but it will idle perfectly and not stall. What does this mean??? BTW A/C doesnt work even with new ccrm.

I think its fixed!!! I pulled off the complete pcv line and noticed that it slid way too easily off the intake manifold. Checked the line and elbows and they were both like new no cracks. Well i tried pulling the one that goes on pcv off and its pretty firm. Then the one on other end slides right off. I blew air into it while covering both holes and air escapes from the end on intake manifold. Its as if the holes where you insert the pipe and mani stem stretched out. Dont know if previous owner put a wrong one on and it eventually stretched or if it was just ???. But i bought a temporary regular elbow off autozone and it idles fine with temp switch plugged in. And it doesn’t stall while coasting. (Going on cruise to test to see if the problem is gone. Dont wanna get worked up for nothing like i have for every part ive changed. Thanks will post whether or not problem is completely gone tomorrow. I couldnt hear hiss since it was leaking from intake mani and car was making enough sound stumbling. Good call on vacuum leak. Thanks.

BTW what the heck could be wrong with a/c.

I hope that finally fixes it for good for ya. About your A/C, it could be that a part of the system piping along the firewall is broken. I know I had a test done on mine and it leaks or something back there. They said it’d be over $300 to fix so I’m just sticking with my 2-70 a/c (windows down).

  • Darron

Same here if it costs any more than 50 bux to fix ill just pull my a/c system out. Ya looks like car is working fine now. Just need to go get a real rubber elbow that can take the heat on monday. I just got a generic rubber elbow at autozone and they mentioned it will probably crack soon.