i got an ol 94 6cy thats pretty much of a lemon for the "famous 300". In two years, ive changed a leaky gas tank, shot balljoints and front tires to go with it, changed the catalytic converter, exhaust and muffler, new radiator and it ran good for a while. About a year ago, i noticed that the oil had a gas smell to it, so i figured better get the injectors cleaned. Mechanic said the fuel pressure was fine, and the gas was probably associated with short driving trips in cold weather. Ok. A couple of months ago i noticed that the engine stumbled, misses and idled irratically, kind of like it had a big cam or something. Also had a hard time reaching operating temperature even after a driving for 2hrs. with lots of condensation on the filler cap that looked like mayonaisse. so i changed the thermostat, then the distributor cap, coil, rotor and wires, new sparkplugs(lots of carbon buildup). Now the condensation is gone, it warms up, but under no load it still had an occasional miss and alternating rpm ranges. And the gas is still in the oil. There is also a noticeable noise coming from the rocker arm cover, no ticking- but a noise that kind of sounds like a diesel. My mechanic says its probably the fuel pressure regulator, and not the EGR valve, (even though the computer has an error code for it). The egr tube to the exhaust is much further upstrem then it used to be since i got the cat changed. But the engine ran fan for over a year after the cat was changed and new oxygen sensors. Im wondering if the engine stumble, gas in oil, and rough running is all asociated with the FPR going bad and getting worse, or a bad egr valve? Any feedback would be greatly appreciated! Its driving me nuts!

 

I may not be the best person to answer this since I don't know your exact engine. Unfortunately, the symptoms you describe are familiar. I had them in a small block V8.

If you can get it done cheaply have someone do a compression test on all cylinders. I had a broken ring (bottom one, the oil seal ring) that split into two pieces. I lost just enough compression to notice.

The car ran rough, there was fuel in the oil and there was a noise I couldn't find. It ended up breaking down the oil and ruining the EGR valve etc., etc. etc.

There was just enough of a compression drop to tell us where to look.

I hope this isn't what you've got.

Chuck

 

What code is it throwing? A lot of the time in an extremely cold climate a short drive will not bring the truck up to operating temperature. I am truly sorry that you've had a bad experience with the 300 I6. I really is a super motor. Take the vacuum line off the fuel pressure regualtor and see if gas is present. That is a dead give-away for a failed FPR. You can test the pressure at the schraeder valve (looks like a tire stem) on the fuel rail with a borowed gauge from the local friendly parts store. If you can, compression test the cylinders dry, then wet. You should get a fair look at the condition of the rings/cylinders. How do your plugs look? Are they sooted up with fuel? If not the FPR (and I'm betting it might be bad) take the EGR off and check for any obstruction/binidng in operation. Start here. Hope we can help you clear this up.

 

I know this thread is ancient, but I thought I'd try my luck. I'm experiencing similar symptoms as the guy who started this thread. I've got a '94 f150 with a 4.9 inline 6 with 179,000 miles and this truck has seen better days. My oil level has gone up, my oil pressure has gone down, the oil smells like gas, I've got steady ticking when under load, and it does sound kinda like a diesel. It's got new injectors, and the cylinder head was serviced recently. I found this thread when doing some research, and seemed like I might be in the same situation as the thread starter but there is no real conclusion here. Does anyone know what the resolution was?

First post here, thanks a lot guys.