Engine nearly stalls out when coming to stop.

[61dragon]

Hi,

I live in TX and have a 1991 Nissan 240, with manual trans and 133.000 miles.

My car normally idles at 900rpm but when coming to a stop, when I depress the clutch the idle goes down to 200 or even1500 rpms. After I come to a complete stop, the idle then goes back to 900 rpm.

I have been told everything from fuel tank debris to computer going out.What can possibly be the problem?

Thank you,Ken

[180fan]

could be a vac leak, your fuel pump going out, your fuel pressure regulator not holding pressure, the switch on your clutch pedal not working right, your iacv going out, or your timing could be boo boo.

So lets start with more info on the car. Have you done a tune up on your car recently? Have you checked your timing, etc.

[61dragon]

Hi,

About 4 months ago, I gave the car a tune up. I replaced the plugs, fuel filter in the engine compartment, cap and rotor. I checked the engine timing and everything else ran fine.

It's just been this week that I noticed the change in idle when coming up to the light.

You mentioned the fuel pump possibly going out but would it lose pressure when coming up to a light? How about the possibility of junk in the gas tank clogging up the gas tank filter?

Thank you,Ken

[180fan]

Probably not anything like junk in the tank. But sounds more like a bad iacv.

[Touchdown038]

Also check the brake booster hose for cracks.

[61dragon]

A friend suggested that it may be a throttle position sensor. Would this part maybe also at fault?

Ken

[lilleo3512]

I just took my car in to the dealership and i had the same prob. but my car also idled rough. They told me my timing chain jumped a tooth now i have to wait till at least monday before i can get my car back cuz i have to wait for an insurance adjuster to look at my car from the warranty company which sucks.

I miss my car already

[rogoman]

The problem with the idle that you're encountering may be the TPS system or the IAA adjustment. The first thing to check is the TPS harness connector pins. The connector is located on the passenger's side of the motor just above the throttle assembly. Look at the pins and see if there's oxidation on them. If so, clean them with fine steel wool then lightly coat them with 'dielectric lubricant' which you can get at most auto parts stores.

For a procedure on adjusting the TPS, go the http://www.240sx.org web site, FAQ section and look up 'Throttle Position Sensor DOHC'.

To adjust the IAA, Fully warm up the motor. Shut motor off. Disconnect the TPS harness connector. Start motor. Check the idle speed. It should read 650 RPM; If not, adjust the idle screw until you get 650 RPM. The idle screw is located on the passenger's side of the motor near the firewall below the intake manifold. Stop the motor. Reconnect the TPS harness connector. Start motor. The idle speed should now be 700 RPM.

As a side note, make sure the air filter is clean. If it's got 15,000 MI on it, replace it.