I have a 1994 Jeep Grand Cherokee Limited (5.2 V8). It ran fine when I bought it from my mechanic friend. After a few weeks it began to sputter like it would die while driving it. A few friends mentioned it my be the fuel filter. My mechanic friend suspected the spark plugs. We replaced the spark plugs and cables. That didn't solve it. So we thought the coolant sensors were bad, so we replaced those. No fix. Then the Check engine light started coming on throwing code 27 (fuel injector code). I checked the voltage on the injectors, and my friend looked at them. They seem fine. It runs super rich, and their is smoke coming out of the exhaust and liquid at times too (I thought it was unburnt gas, but it seems to be water). We then thought it might be the o2 sensors. We went under and found the Catalytic Converter had been removed, along with the down pipe o2. The upstream o2 was still there. It read bad, so we changed it. No dice, though. I then decided to change out the throttle position sensor and the idle air control valve. I was sure it was the IAC. After replacing those two things and reseting the Jeep's computer I took it for a drive. Felt like it was running a lot better. Slight surge when driving, but I attributed it to the reset computer. I ran it for awhile to get the temp up, then stopped it. Went back and drove it some more, but it seemed worse then before. Now it almost seems like it has no power. I step on the gas, peddle to the metal, and it only slowly climbs in speed. As always, while idling, if I tap on the gas the RPMs go up, then go to zero and the Jeep sputters and dies. Any ideas? I think I have replaced everything that could be the issue. My friend wants to try replacing the rotor and distributor.

 

The fact that it is running super rich, smoking and a lot of moisture, makes me suspect a mechanical problem which is leaking fuel into the intake. I'm not sure, but I don't think the computer could put that much extra fuel in if it tried.

I don't know where the fuel pressure regulator is on it, but some vehicles have them in the intake where any leakage is burnt up in the engine. If it leaks bad, it will cause the engine to run really rich. Also, fuel injectors can develop leaks and let extra fuel in.

 

Changed the rotor cap and pick up coil. Still no fix.

 

No one have a clue?

 

A 94 does not have a down stream O2 sensor. Your mechanic friend is not much of a mechanic. Do a compression test, if you find a low cylinder you will then do a cylinder leak down test to see where the problem is. Air coming from the oil fill cap indicates bad rings. Air from the exhaust means a burnt exhaust valve. Air from the throttle body means a burnt intake valve. The 5.2 also has a plate on the bottom of the intake manifold that will leak, it will cause a vacuum leak and oil consumption. Water from the exhaust is a normal thing. Is there an EGR valve on this engine?