I'm driving around a 1992 E150. 300 Inline 6, 4.9L 187,000 miles on it. I'm getting gas in my oil. I just changed it and I got a good extra quart of liquid. Running rich, buildup in exhaust pipe. Its definately losing compression. i havent much power to get up any steep hills faster than 35 mph. blows a little blue smoke sometimes if i stomp on it, or if i dont let the engine warm up. not running quite as smoothly as it used to. throws a couple codes.
mass air flow high
heated O2 sensor rich left
egr valve position sensor voltage low
thermactor air system inopperative right
heated O2 sensor slow response.

yikes. a lot happening with this all at once.
what are you thoughts on the fuel system?
where should i start?

 

Under all that electronic gobbeldy-gook there is still an engine. Some of those codes may be due to a missing cylinder(s). First I would see if there is a weak or dead cylinder to help you isolate the problem(s). This can be done with a cylinder drop-out test, an IR thermo gun aimed at each exhaust runner, or by the ole saliva sizzle method.
Then I would look to see where excess fuel is coming from. On an EFI engine there aren't many places - a leaky injector or a ruptured fuel pressure regulator diaphragm.
If it went on long enough, the fuel could have wiped out your rings. Good luck.

 

did a compression test. all six came in at 150-155 dry. around 165 wet. i'm thinking rings?

but there is a problem. everything's back in place and it wont start. turns over. i can smell gas. perhaps i damaged the coil?

 

Your compression numbers are fine, in fact very good.

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Back to stuck injector, fuel pressure, but first check your connections and firing order to get it to run again.

 

i checked the firing order and its fine. connections are fine. coil has some fine, white corrosion on it. not much but enough to worry?

 

Follow the electricity. Start at the battery, head towards the plugs. When you stop getting a reading, you're there. Clean the corrosion off and see what happens. You should clean it anyway, and it may be your lucky day!

 

Replace the O2 Sensor(s)?

Double check the EGR is operating and vacuum lines hooked up proper?

Thermactor is that Airpump that a lot of people delete. Not sure what happens on EFI controlled 300's if it's deleted...

Fix those and I'm sure the Computer will be happy and not be stuck in 'drive home' mode (Dumping fuel into engine like crazy).

 

Alright! All is good now. I used a spark tester to test my coil... Junk! Got a new one and installed it. Starts up better than before. Prolly because it was alot more corroded than I thought. the post was all mucked up and fallin apart. prolly the original. any how, while i had it pulled apart monday, i was pokin around and found 2 vac lines unplugged, EGR unplugged and a dirty MAP sensor. turns out i dont have a mass airflow sensor either. so i cleaned and fixed them little ****s and I have no more codes. added some engine restore and i can already feel a difference. still blowin some white smoke, not much. i also found a small exhaust leak by the manifold. so thank you all for your input and assistance. I really appreciate it. let me know if you have any more tips.