Strange Issue after warm up

[awoll_1]

Hello All,

Been fighting with this 87 Ford Ranger 4x4 for over a year. I'll cut to the issue first, then what I have already done.

The truck starts up fine, in both cold and warm weather. It drives fine when cold, and for about 15 mins after warmed up to temp. After about that time, the engine starts to bog down, sounds like its missing and even backfires when you give it gas.

I've replaced both fuel pumps, checked with a fuel pressure gauge ran into my cab that the fuel pressure is good, and regulator operates properly. Full tune up, down to the air cleaner. Brand new Distributor, and IPS, IAC and air temp sensor, new coil. Timing is set at 10 degrees with the spout out, after warmed up. No signs of a vacuum leak. I got the truck with out an overflow bottle, so was concerned about the water loss, installed an aftermarket container, and no water has been lost since. No oil in the water. Checked the TPS with analog mulitmeter and it specs out fine, as well as the water temp sensor to the ECU. I also bought a code reader, and no codes are present in the system. Oh fuel filter has been replaced along with an injector rebuild kit.

Any ideas?

 

[bf750]

bad converter can do that

 

[awoll_1]

bad converter can do that

If your referring to a catalytic converter... it doesn't have one. Muffler is pretty blown out too.

 

[bf750]

have you changed the map sensor

 

[RonD]

You said you checked the ECT sensor, that's the TWO wire sensor only used by the computer?

There is a temp SENDER that looks similar, but only 1 wire, it is only for the dash board gauge.

ECT sensor is a resistance sensor, as it heats up resistances goes up.
Computer sends it 5volts on one wire
Computer gets back "temp voltage" on the other wire, 3volt is cold, under 1volt(.5v) is warmed up.

You can tell ECT sensor is working if your idle starts out at 1,100+ when cold, and then slowly goes down, over the next 5-8 minutes, to 650-750RPMs when warmed up.

 

[woooody]

Find an answer yet?

Having the same issue - acts like a vacuum leak after about 15 minutes. Keeping the RPMs up and higher speeds keep it from what seems like misfires and trying to die.