I have the most complicated saturn here plz help

1994 Saturn SL1 5spd manual

Okay, so car stalls randomly and the idle becomes eratic in neutral before stallout. Think you know whats wrong? think again because I doubt anyonr can help me at this point, been struggling on the side of the road for over 5 months of troubleshooting, if you have the answer I would be surprised, and you would be smarter than what is now half a dozen mechanics, but Ill take your ideas, like if you have experience with the MAF doing this, any advice is appreciated. Car runa great other than this issue, Ive driven 30,000 miles like this but the problem has gotten worse and now the car will stall everyday when the day warms past 65f or so. Here is what I replaced, I will never, ever, ever ever ever buy another saturn btw NEVER! Vehicles paint looks almost brand new after 30 years. Car seems in great shape but WTF with the random stalls.....here is what I replaced...and no there is no check engine light or codes

Fuel Pump
Alternator/generator
Battery cable connection
Battery
ICM
Both ignition coils
Sparks
Spark cables
Idle air control valve
Crank sensor
Throttle position sensor
Throttle body
Clutch hydraulics(unrelated)
Idler pulley(unrelated)
Drive belt(unrelated)
Key ignition cylinder(unrelated)
PCV and EGR hoses
Fuel filter
Air filter
Air filter housing gasket

I literally took a saw and sawed partially into the gas can and almost blew up replacing the fuel pump redneck style through the seat trunk area. Im 37 and in my entire life I have never cried and bled and shouted at the heavens more off of anything, not even close, never have the right tool no matter how many I buy. I am so exhausted and 1500 miles from anyone I know trying to fix this in the deserts, I dont know how to give up but I have literally gone insane. Advice? How does anyone decide and follow through with being a mechanic is beyond me, Im ready to give up driving if I cant fix THIS CAR.

my last remaining ideas, let me know why theyre not it or why they might be

MAF sensor, should I tap on it or unplug it with the car on? What electrical readings can I look for on a multimeter?

Catalytic converter, does it get clogged when its hot? I dont smell any gas smells after I replaced the coils and ICM, but did prior very rarely

Engine temperature sensor, this was jimmy rig soldered onto ground, I unplugged it car still runs with it plugged or unplugged

Speed sensor, really??,

O2 sensor, really?

Some sort of engine compression issue or head gasket leak that only acts up when the car stalls?

Doesnt seem like fuel injectors would fail simultaneously like this, am I wrong?

Cam sensor?

Some electrical cord?

WHAT AM I missing?

 

Good that you renewed the IAC valve.
Suggestions (what maybe missing):
1. On '94 S series, the EGR is mechanical, thermo spring activated. These require more replacement than the later electric actuators. I would renew the EGR valve.
2. The ECT ElectricCoolantTemperature sensor is important to fuel mixture (etc.) and has lots consequences.
Replacements are cheap. Have new one ready to thread in before remove existing (else leaks coolant)....
It is important that the ECT connections to wiring harness are proper (polarity does Not matter) and good quality.
3. Consider replacing the electrical Connector at the termination of wiring harness for both the IAC and the ECT.
{Or do serious troubleshooting of those component circuits}. The harness connectors do fail....

Be mindful that the OnBoard Diagnostics (OBD1 here) are generally first step in troubleshoot cars with computer controls. Suggest procure an OEM (Helm) Saturn MANUAL for that year of car. The Throttle Body Injection cars were Very Reliable and contributed to the good reliability reputation (only obsoleted for fuel efficiency reasons).
If you have a Smart Phone, can get APP which (with ELM hardware interface) can yield Real Time data....
I would renew the EGR & ECTs & FuelPressureRegulator before doing the better scan tool thing.


I have not worked on the ThrottleBodyInjection on those year/models.
4. I would locate the FuelPressureRegulator. The fuel pressure regulator on 96-98 can STICK and mess with injection hence Mixture (later years FPR included with filter).
Both the IAC valve and EGR can mess with airflow (hence Mixture of fuel/air) which is critical near/at idle.

 

Engine Coolant Temp sensor. Long time Saturn owner. That’s your problem, it’s integral the the car and how well it runs.

 

There is no MAF on those Saturns, it's a MAP a much simpler sensor. As a first step I suggest to use a OBD 1 paperclip mod to read OBD codes through CEL blinks.




TROUBLE CODES
11 Transmission Diagnostic Trouble Codes Present
12 Diagnostic Check Only (Flash DTC)
13 Oxygen Sensor Circuit - Open/Not Ready
14 ECT Circuit - Temperature Out of Range High
15 ECT Circuit - Temperature Out of Range Low
17 PCM Fault - Pull-up Resistor
19 6X Signal Fault - No 6X Signal Between Reference Pulses
21 TP Sensor Circuit - Voltage Out of Range High
22 TP Sensor Circuit - Voltage Out of Range Low
23 IAT Circuit - Temperature Out of Range Low
24 VSS Circuit - No Signal
25 IAT Circuit - Temperature Out of Range High
26 Quad Driver Output Fault
32 EGR System Fault
33 MAP Circuit - Voltage Out of Range High
34 MAP Circuit - Voltage Out of Range Low
35 Idle Air Control (IAC) - RPM Out of Range
41* IC Control Circuit - Open or Shorted
42* Bypass Circuit - Open or Shorted
43 Knock Sensor Circuit (KS) - Open or Shorted
44 Oxygen Sensor Indicates System Lean
45 Oxygen Sensor Indicates System Rich
46 Power Steering Pressure Circuit - Open
49 RPM - High Idle (Vacuum Leak)
51 PCM Memory Error
55 A/D Error
81 ABS Message Fault
82 PCM - Internal Communication Fault

*41 & 42 Simultaniously - Ignition Control (IC) Circuit - Grounded/Bypass Open



PCM INFORMATION FLAGS
These information flags do not indicate a failure and will not turn on the malfunction indicator lamp (MIL). Information flags are used as diagnostic aids to the technician when hard diagnostic trouble codes or intermittent problems occur.

- Engine information flags will not be flashed on the malfunction indicator lamp (MIL) and they can only be read with a Scan tool.
- Automatic Transaxle Information Flags will flash on the HOT light.


ENGINE INFORMATION FLAGS
16 Electrical Variable Orifice (EVO) Fault
27 Quick Quad Driver Module
48 Reference Input - Intermittent or Noisy
52 Battery Voltage Out of Range
53 Knock Sensor Circuit - Knock Present
54 Five Volt Reference Ground
58 Battery Voltage Unstable
63 Option Check Sum Error
71 Cooling System - Temperature High
72 Cooling System - Temperature Low
73 ECT Unstable
74 ECT/Trans Temperature Sensor Ratio Error
75 IAT Unstable
76 TP Sensor Voltage vs MAP Voltage - Out of Range
83 Low Coolant Flag
84 PCM - Internal Communication Failure

 

I had a similar issue when I first bought my 1997 SW2 with standard trans.

It turned out to be a grounding issue.

Locate the rear grounding blocks and check their condition. Mine were corroded A_F_, causing the current to loop back around the system rather than going to ground. Became most noticeable when I turned the headlights on, or when the brake lights came on.

Another symptom I noticed, and the one that led me to put things together, was this : I was sitting in the car, racking my brain and going over all the things I had tried (more than I'd like to admit - including the alternator). I pressed my foot on the brake and I heard something faint near the rear seats.... Turned off when I let off the brake. I traced the sound and figured out that the fuel pump was turning on! The current was going back around and dumping into various other circuits rather than to ground.

I dunno if you have fixed this issue yet, but something to check out.