No codes

[Johnny Creeps]

My truck, 94 4.0L Ranger, runs like perfection, then when I put it in park, it dies. When I restart it, the check engine light comes on (but I can't get it to flash codes for me) and it chugs and is dumping gas into the system. To me, it was obviously the O2 sensors... changed both of those and it's still doing the same thing. Any ideas?

Creeps

 

[adsm08]

Check the vacuum line to the fuel pressure regulator for liquid fuel. It has a rubber diaphragm in it that can rupture and allow liquid fuel into the vacuum system.

 

[RonD]

Welcome to TRS

O2 sensors wouldn't cause that, they are not used at idle or for starting.
But if engine has over 150k miles then they needed to be changed.

On the fuel rail, passenger side front, on lower intake will be the FPR(Fuel Pressure Regulator), by the alternator.
It will have a Fuel line connected, the return fuel line, and it will have a vacuum line connected.
You need to check this vacuum line for fuel or fuel smell, it runs from FPR to rear of engine then around the back of upper intake to the Vacuum manifold on drivers side upper intake, where brake booster is connected.
If FPR diaphragm is leaking then raw fuel will be sucked into the intake via this vacuum line when vacuum is high, like at low RPMs/idle.
If there is fuel in the vacuum line then replace FPR.

Another possibility is the IAC(idle air control) Valve.
This wouldn't cause a gas smell though, but can cause engine to stall and be hard to restart.
It is on the upper front of the intake looks like a tube mounted sideways and has a two wire connector, this can be cleaned.
How-to with pictures here: http://www.explorerforum.com/forums/index.php?threads/how-to-iac-valve-cleaning-thread-w-pics.84220/

Has your MPG dropped recently?

 

[Johnny Creeps]

I'm okay with wasting the money on the O2's as I'd have needed to eventually anyway... you're the third to mention the FPR, so I will check that tomorrow. As for mileage, yeah, it was running fine, used about an 8th of a tank to go 90 miles... the return trip used 3/4 of a tank, so it was definitely dumping the fuel. The tailpipe, which is new and still shiny stainless, is all black and when the engine is chugging, it puffs thick black smoke and smells like straight gas.

Welcome to TRS

O2 sensors wouldn't cause that, they are not used at idle or for starting.
But if engine has over 150k miles then they needed to be changed.

On the fuel rail, passenger side front, on lower intake will be the FPR(Fuel Pressure Regulator), by the alternator.
It will have a Fuel line connected, the return fuel line, and it will have a vacuum line connected.
You need to check this vacuum line for fuel or fuel smell, it runs from FPR to rear of engine then around the back of upper intake to the Vacuum manifold on drivers side upper intake, where brake booster is connected.
If FPR diaphragm is leaking then raw fuel will be sucked into the intake via this vacuum line when vacuum is high, like at low RPMs/idle.
If there is fuel in the vacuum line then replace FPR.

Another possibility is the IAC(idle air control) Valve.
This wouldn't cause a gas smell though, but can cause engine to stall and be hard to restart.
It is on the upper front of the intake looks like a tube mounted sideways and has a two wire connector, this can be cleaned.
How-to with pictures here: http://www.explorerforum.com/forums/index.php?threads/how-to-iac-valve-cleaning-thread-w-pics.84220/

Has your MPG dropped recently?

 

[Johnny Creeps]

Thank you... I will get on that tomorrow and see what happens!

Check the vacuum line to the fuel pressure regulator for liquid fuel. It has a rubber diaphragm in it that can rupture and allow liquid fuel into the vacuum system.