88 Foxbody Starts but Stalls When Warm Please Help

[airforcerob]

Hi I've been working on my 88 5.0 Mustang for about 6 months and cant seem to figure out what's wrong. I pulled the engine to replace the head gasket and to do a general overhaul. Everything went well and it fired right up after getting the timing set. It runs great at start and once reaching operating temp the idle starts to surge and gets worse until it eventually stalls. Codes call out O2 sensors but on both sides. Any help is apricated! Most of the new parts are listed below.

Head Gasket
Valve Cover Gaskets
Water Pump
Rear Main Seal
Oil Pump
Oil Pan & Gasket
EGR Valve
Fuel Pump
Fuel Filter
Spark Plugs & Wires
130amp Alternator
BBK Exhaust Headers
Coolant Temp Sensor
Intake Air Temp Sensor
T5 Fluid
Clutch and Pressure Plate
Resurfaced Flywheel
R134a Conversation
A/C Clutch Cycling Switch
A/C Condenser
Evaporator to Condenser Line
Accumulator
Compressor Discharge Line
A/C Service Attachments
High Side Adapter
Lager Battery

 

[AeroCoupe]

Check the ten pin connectors and make sure you are getting good connections. You may need to close the female connectors and open up the male connectors to get a better connection. The O2 sensors run thought these connector and they have been known to cause issues.

 

[General karthief]

^^^^ what he said ^^^^
And check for vacuum leaks too.

 

[airforcerob]

Check the ten pin connectors and make sure you are getting good connections. You may need to close the female connectors and open up the male connectors to get a better connection. The O2 sensors run thought these connector and they have been known to cause issues.

Thanks I'll give that a try. By 10 pin connectors those are the salt and pepper looking ones behind the plenum?

 

[gkomo]

Thanks I'll give that a try. By 10 pin connectors those are the salt and pepper looking ones behind the plenum?

Correct

 

[rwordenjr]

Those are the only 2 codes you have?

 

[Noobz347]

O2 sensors - rich ?

--or--

O2 sensors - lean ?

--or--

No Switching Detected ?

--or--

Other?