Rough idle warm restart 02 vulcan – taurus car club of america ford taurus forum grade 9 electricity questions

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Hello all. My 6th Taurus/Tauri? I’ve searched here and various Ford sites for a repair, have tried multiple suggestions to no avail. Bought this 02 SE wagon Vin U non flex from a yard last summer. Prev Texas car, solid body. Kinda rare in Wi. At that time had misfire codes cyl 1 2 3, multi misfires ran like crap. Ac pulley bearing was frozen and serp belt laying on the subframe. Oil was clean so pulled the heads. Both cracked. Sourced a set of heads, had them rebuilt, new gaskets and head bolts correctly torqued. New Ford coil, plugs, fuel filter, oil change, gold coolant, wires. Started and ran like a champ. 2 months later fell on her face merging into traffic and set the mil. Forget the exact code but fuel rail pressure sensor fuel pressure low. With 180k, ordered a Delphi fuel pump assembly n installed it. Replaced a Carter. Ran fine, no more running out of steam merging. 2 months later sits for 30 mins after a 40 minute drive. Cranks, starts, n then idle varies. 200/ 800., shakes the whole car. Apply gas pedal, no change. Mil flashing. Ive pulled the upper intake to see if injectors are leaking down, have pinched off every vac line on this car while monitoring data with a OTC Genesis. Fuel press at start, cold, 42. Warm ie above 200, 56 n drops as it runs. When this hiccup occurs upstream 02s, both, lay at almost zero, long and short term kick in enriching up to 33%, car then kinda shakes itself n all is good. Have checked coolant temp sensor reading, reads 220 and verified with temp gun. Im suspecting a pcm or upstream 02s but for both to fail at same time? If I start this car cold, or 50 mins after parking hot, as long as I stayed out of the 30-40 min hot soak, I could drive it around the world. Have to figure this out as summer is on its way. Thanks! Dan

Hello all. My 6th Taurus/Tauri? I’ve searched here and various Ford sites for a repair, have tried multiple suggestions to no avail. Bought this 02 SE wagon Vin U non flex from a yard last summer. Prev Texas car, solid body. Kinda rare in Wi. At that time had misfire codes cyl 1 2 3, multi misfires ran like crap. Ac pulley bearing was frozen and serp belt laying on the subframe. Oil was clean so pulled the heads. Both cracked. Sourced a set of heads, had them rebuilt, new gaskets and head bolts correctly torqued. New Ford coil, plugs, fuel filter, oil change, gold coolant, wires. Started and ran like a champ. 2 months later fell on her face merging into traffic and set the mil. Forget the exact code but fuel rail pressure sensor fuel pressure low. With 180k, ordered a Delphi fuel pump assembly n installed it. Replaced a Carter. Ran fine, no more running out of steam merging. 2 months later sits for 30 mins after a 40 minute drive. Cranks, starts, n then idle varies. 200/ 800., shakes the whole car. Apply gas pedal, no change. Mil flashing. Ive pulled the upper intake to see if injectors are leaking down, have pinched off every vac line on this car while monitoring data with a OTC Genesis. Fuel press at start, cold, 42. Warm ie above 200, 56 n drops as it runs. When this hiccup occurs upstream 02s, both, lay at almost zero, long and short term kick in enriching up to 33%, car then kinda shakes itself n all is good. Have checked coolant temp sensor reading, reads 220 and verified with temp gun. Im suspecting a pcm or upstream 02s but for both to fail at same time? If I start this car cold, or 50 mins after parking hot, as long as I stayed out of the 30-40 min hot soak, I could drive it around the world. Have to figure this out as summer is on its way. Thanks! Dan

Fuel pressure matches scan tool info with reference vacuum to fuel rail press sensor disconnected. Normal ie cold fuel pressures 41psi. As I understand warm/hot logic on this returnless system, higher pressure at restart to compensate for a "hot" fuel rail. It does this. Odd is both upstream 02’s showing lean, stuck at .02 volts. Bumping the gas pedal, they do "wake" up n begin to switch from .84 to .44 back and forth. Once they wake up all is fine.Did you do the fuel filter? And as to pump: my ’03 had fuel pump not start but I could start and back out of my drive before it hesitated and choked down to dead. I could hot wire the pump and drive it with max pressure = 80#. Drove it to a shop for fuel pump replace. The fuel pump module senses current and if the pump draws too much it will default. However if I hot wire it to pump up pressure and then let it stop: I could start and it would idle down to pressure under 10# according to Ultragage readout. So on startup they will start and idle normal until the fuel under pressure in the line is used up. No abnormal idle until the pressure is very low. When started the O2 sensors will not operate for a short time due to need to heat up first. Heat is made by the heater in each and the exhaust heat. No reading when started does not mean lean, just waiting to get enough heat to go to work. When started, the engine runs on open loop, meaning it runs on pre programmed parameters until the loop closes with the O2 sensors getting hot and working.