Thanks for all the help so far guys. This has been the most frustrating problem I've ever had with my 1992 240. Here's a quick summary of the original problem, steps I've taken, and current condition of the vehicle.

1. Original Problem: Car would idle terribly at start-up. The problem seemed worse when the gas tank was near empty. The car stalled a few times and threw a check engine light and codes about the fuel being too rich/too lean and something with a fuel injector fault.

2. Steps Taken: I did find a problem with the air intake hose where one of the nipples had broken off on the back side that connects to the flame trap. So I have a new one in there now.

I also checked the vacuum hoses and replaced some of them.

The poor idle and engine shake was still happening so I went ahead and replaced the original in-tank pump since the vehicle has almost 200,000 miles and the problem seemed worse when the tank was low.

Unfortunately the engine shake still occurred and the idle was still poor after the in-tank pump was installed. I checked the operation of the pump using Art's method by removing the fuse and jumping the left vs right sides to activate the in-tank pump and external fuel pump independently.

I have checked and verfied that spark comes through the spark plug wires on all cylinders.

I have searched for vacuum leaks at the throttle body and cleaned the throttle body.

Last night I replaced the original oxygen sensor with a Bosch unit. The idle seems a little less erratic and the engine shakes a little less, but it still isn't smooth and it still seems like it is missing sometimes.

The fuel pressure regulator does not have gasoline leaking out of it when I remove the vacuum hose from there.

Current Condition: Car is driveable, but idles poorly at start up. The engine shakes some like it is missing or stalling. Not bucking as much as it was before the oxygen sensor, but still not acting quite right. When I leave my parking spot, the vehicle sounds like some sort of old fashioned car that is running really slow and erratic. Kinda almost like those funny cars at idle at the starting line before a drag race. It could be my imagination, but it seems like the exhaust smells of gasoline.

There was a suggestion for me to check the individual spark plugs. I can easily pull them, but I'm not sure what to check for.

Thanks for reading my long post.

Did I mention that Chad Henne stinks?

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