Car stalling and idling issue

[mousetom78]

Ok .. it is driving me nut. We have a 1993 Lumina 3.1L v6 has intermittent idling and stalling problems. Sometime it won't start and it will stall. We have to do a neutral drop to get the car going. It will stall in traffic when it runs hot after 15 mins. Sometime, it will run like a champ for little while with no stall. Problems started about 2 months ago and we have been trying to fix since. It is throwing intermittent engine code. We have a computer code scanner and monitor for the ODB I. It is throwing intermitent random codes on us 25 (MAP Sensor), 33 MAF Sensor faulty/Vaccum), 44 (faulty O2 sensor), 32 (EGR Error). 35 (IAC Sensor) Here's a list of items we replaced. Same error codes come back even after we replaced or tried mutliple sensors. How many O2 sensors are on the luminia? Are there 1 or 2 O2 sensors? We replaced the one under the hood in the back behind the firewall. Are there anyone in the back of the car? Is it possible when it has bad ECM or prom chip? Anything else can we look at?

 

New O2 Sensor

New spark plugs/wires

New MAP sensor

We tried 3 EGR valves from junk yard and we put a "block off" plate

New TPS (thottle postion sensor)

New IAC (Idle Air Control) - 3 of them new and used one from junk yard

We cleaned the throttle body and and platium with carb cleaner

We visual inspected vaccum lines (it looks fine) but we dont have a vaccum guage.

Battery/Alternator test passed with autozone and advance autos

An Spark plug coil module from junk yard and we inspected coils and swapped couple of them but it is still doing same shit.

 

It stalls more likely on cold start but it stalls when it warms too. It just wont idle but we get it going with nectral drop.

[Slade901]

I would remove and clean the CTS (Coolant Temperature Sensor) or probably replace it. If the CTS is failing it will give incorrect temperature reading and computer uses the CTS reading to adjust the fuel injector opening/closing for specific times.

 

I'm not sure where your ICM/Ignition Coil packs are located. On my 1990 Olds Cutlass, the ICM/Ignition Coil packs are located directly below the center front of the engine and above it is the coolant reservoir. Overflow fromthe coolant reservoir after the engine is at operating temperature, the excess coolant comes out and sprays/squirts coolant directly down to the ICM/Ignition Coil packs and causes bucking/driveability problem and sometimes the engine dies. I've made sure that the excess coolant from the coolant reservoir comes out of the overflow tube and away from the ICM/Ignition Coil packs.

 

Replace your PCV valve if you have not replaced it. It might be stucked closed and allowing air/oil vapor to come out instead of the breather hose and into the intake and causing the fuel octane to lower and causing detonation problem (too much engine temperature caused by detonation or pre-ignition).

 

I've set up my dual fan and connected it directly to the primary fan and it cools down my engine faster.