Go out in AM, car is cold, starts and runs fine. Drive short distance, stop and restart, runs fine, idles fine. Drive about 8 miles at 50-55 mph, pull up at a red light, when speed gets down to ~25-30 mph, car stalls. Carburetor has been rebuilt. Put car in neutral or park right after it stalls - it starts right up and will run until you slow down to 30 mph or slower, stalls, As long as choke is closed enough, it seems to run fine. We really appreciate your help. It has been a major problem for months, and multiple shops have been unable to fix it.

Engine stops running or transmission stops pulling ?

The usual cause of this is a bad PNP switch or gear position sensor.
The "W" is flashing because the transmission control module is stuck in the Winter mode. If you are not familiar with sensor, I suggest you go and have the transmission codes read and reset to begin with and then post back the results.

well lets try inspecting your coolant temp sensor for the ecu, not for your gage it is green whit two wires going into it, if any corrosion replace sensor and pigtail, your ecu may be dumping lots of fuel thinking eng still cold when is hot, this also wahs off your rings and by adding oil bumps compression and starts, hope this helps.

The choke not opening up(from cold to hot). Bad air and fuel filters. If you have a mechanical pump, they work or run bad all the time or don't work. If you have an electrical pump, it to could be going bad.

Check for vacuum leaks and read other tips at link below.
Do It Yourself Diagnosis and Repair

You mean PCM most states read the readiness monitors depending on the state on how many they allow not to be completed. The first one on the list that is hard to get run and pass is the EVAP Because this requires the car to be cold and fuel tank must between 15%-85% and both air temp and coolant temp with in 10 degrees of each other. Start car let idle for 5 -10 minutes Then drive car normally no hard accelerations or quick stops bring speed to 50-60 mph and coast down to 20-15 mph without brake pedal input repeat this twice.Then bring speed to 58-62 mph and set cruise control run for 12-16 miles exit freeway caught a red light or stop and idle 2 minutes shut car off rest for 5 minutes and repeat freeway drive. then redo morning cold start again . then have some one test the generic readiness monitors to what needs to run and attempt again. California before 2000 1 can be incomplete after 2000 all have to be completed which is hard some will not run for 800 miles.

Hello! I need the trouble code...The vehicle is an On Board Diagnostic 1 (OBD!)...You can not use a scanner on an OBD1...See drawing below of connector under the steering wheel...Short pins A to B...Turn on the key...Don't start the engine...Light on dash will flash the code ie...4 long blinks...pause... 1 short blink=code 41...each code, if more tan one, will flash 3 times...record the code # and send it to me and I'll fix the problem....codes are all two digit... guru...saailer






I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

long post.
ill reduce it for you.
misfires. (is RPM below 700 then misfire can be normal) for idle speed controls dead.
ISC the isc controls speed, of idle,.
mine stuck like zillion times, in 400k miles. endless.sticking
mine was a tiny gutless stepper motor drive ISC valve.
the cone valve is side gets nasty and sticks (
(PCV gases caused as seen on all engines)
i clean it.
the proof is the easy press of right foot easy raises idle back to 700rpm and engine stops misfiring.
ever get a tuneup this decade or running spark parts 500,0000 miles
for the new world record.?


now the tricky part of ISC, , fully explained in the SM serv. man.
the PCM learns its behaviors.
it learns all hot start settings and cold
so when you key on, it goes to the correct HISTORICAL spot.
if it can move there(sticks) engine car race.
or run too slow,
cold start would be worse, as hot isc is more closed
so if sticks there closed, the next cold start will be horrid
some newer manuals telly you to add 5% throttle if car is hard starting this is so common.

clean it. end story.
ISC

it is not how many miles but the type of driving.

here is a OBD2 drive cycle test.

Generic OBD II "Drive Cycle" Most OBD II ("On-Board Diagnostics II") diagnostic monitors will run at some time during normal operation of the vehicle.
However, to satisy all of the different Trip enable criteria and run all of the OBD II diagnostic monitors, the vehicle must be driven under a variety of conditions. The following drive cycle will (theoretically) allow all monitors to run on (??) vehicle. (Note: Drive cycle specifics vary by vehicle!)

1. Ensure that the fuel tank is between 1/4 and 3/4 full.
2. Start cold (below 86°F /30°C) and warm up until engine coolant temperature is at least 160° F (typically requires at least one minute; up to 3 minutes).
3. Accelerate to 40-55 MPH at 25% throttle and maintain speed for five minutes.
4. Decelerate without using the brake (coast down) to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.
5. Restart and accelerate to 40-55 MPH at 25% throttle and maintain speed for two minutes.
6. Decelerate with using the brake [or the clutch!] by coasting down to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.

It can possibly be the crank position sensor mounted on the top of the bell housing on the passenger side of the vehicle causing the problem. I have replaced a few of these for the same reason.