# Idling very bad.Need help.



## Marilyn Mans (Feb 5, 2003)

Hi Guys:Looking for help with this problem. I had my car (sentra 94) tuned up about 3 months ago. New plugs, wires and rotor cap. Had a new muffler put in for inspection also. Today I had this problem that the car does not seems to want to idle at all. It died on me at least 4 times at the stop sign. When I put it back in park, It starts. Any idea what that might be.I have to kind of play with the brake pedal (kind of press/release a bit stuff), just as you would do with the clutch for manual transnmission. I am totally frustrated, because I just paid $700 to be able to pass inspection.
Many many thanks as always.
Marilyn


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## StevenLK (Jul 15, 2002)

mine does the same i think it dont get enuff air do u hav an intake'?..... or maybe ur vacuum but it happens when i go fast then stop fast or O2 sensor . it's alot of things i dont know either but i think its the intake deal on mine. because i had my head lgiht out and it workd perfect. but i have it back in and doent get much air. and it runs RICHHHH..... but'' when u turn it back on. REv kind of high and slowly come down. then. go.... :-D always work for meeee


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## toolapcfan (Jul 10, 2002)

Here's what the FSM says for poor idle:

High idling after warm up:

1) Check IACV-Air Regulator; When pinching the IACV-Air Regulator hose, does the engine speed drop? If yes, theck the regulaotr and circuit.
If no, then go to #2
2) Check intake air leak; Disconnnect O2 sensor, After racing engine to 2K rpms for 30 seconds, does the engine speed drop? If yes, then you have and air leak. 
If no, then go to #3
3) Check throttle linkage; make sure it moves smoothly and that the throttle valve fully closes and opens when the throttle is operated.

Unstable Idle:

1) Check EGR valve for sticking
2) Perform Power Balance Test; disconnect one injector at at time 
(uplug one, then plug it back in, and so forth for each injector) and note if there is any cylinder which does not produce a momentary engine speed drop? If all produce a momentary drop, go to #6, if one or more don't produce a momentary drop, go to #3.
3) Check injector; Does the injector make an operating sound? If not check the injector and it's circuit. If the injector does make an operating sound then go to #4.
4) Check ignition spark; Disconnect plug wire from plug, place a known good plug to the wire. Place the threaded portion of the plug against a suitable ground and crank the motor over and look for spark. If there's no spark, check the ignition coil and transistor and their circuits. If there is spark then go to #5.
5) Check sprak plugs: check for fouling, etc. If the plugs check out, go to #6.
6) Check Fuel pressure; Release fuel pressure (Remove fule pump fuse and start car, let it run until the engine dies, then crank the engine a few times. Put the fuse back in.) Install a fule pressure gauge and check the pressure. At idle the pressure should be 36 psi. If the pressure isn't right, then check out the fule pump and it's circuit. If the pressure is good, go to #7.
7) Check O2 sensor; *(I'd just replace it, they're like $40, especially if it hasn't been done in a few years). If the O2 sensor is good, then go to #8.
8) Check for air intake leak; when pinching the pcv hose, does the engine speed rise? If yes then you have a leak, if not go to #9.
9) Check Idle Adjustment Screw clogging; Disconnect the TPS and try to set idle to (automatic transmissions only) 725 + or - 50 rpm by turning the Idle Adjustment Screw. If you can't get it to the right rpm, then check the screw for clogging or the throttle valve for clogging. If you can set it, then go to #10.
10) Check compression pressure; Standard pressure is 192 psi, minimum is 164 psi, and the maximum difference between any given clylinders 14 psi. If the pressue doesn't check out, then the pistons, rings, valves, vavle seats or head gasket could be the problem. If the pressure is good, go to #11.
11) Check the ECU harness connector; Check the harness pins for damage or poor connection. If that checks out go to #12.
12) Try and known good ECU.


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## dry (Oct 21, 2002)

thanks toolapcfan I was just about to ask an Idle question but then I searched and found this. I'll go take a look at it in the morning. I think its the throttle linkage. I am idling at 1200-1500 rpm... pretty high eh? but at that high of an idle, I dont think its possible for me to stall, so I think I might leave it at that as I give my neighbor driving lessons for a stick shift


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