[Sportwagon75]

Otto - I appreciate your knowledge and experience. Your input and suggestions are always welcomed. Unfortunately, this mystery remains unsolved. Having numerous 75's through the years, and presently with 4, I'm pretty familiar with the unique parts of these Opels. The fuel "sock" is pretty much a generic expression in my mind for lack of a better term as it relates to the 75. It's more of a fuel pickup "can" and yes it is, indeed, new. This was a tank that I personally cleaned. It looks brand new inside. Secondly...it's a rare occasion when an NOS fuel pickup appears on Ebay. Even more rare when it's for a 75. So, naturally, I responded rather aggressively when one turned up a few months back. (there's a member here who can bear witness to my aggressiveness in acquiring it) So anyway...all fuel lines were cleaned out and all rubber hoses were replaced. The injectors were cleaned and the NOS pickup/sender was installed. Once again…even if the sock/can were not new…the symptoms would be more universal if it were a plugged screen. This is clearly a temperature-related problem that disappears when the weather is cooler. Lastly…regarding your suggestion of a restriction in the fuel return: If this were the case…it would tend to create back pressure at the injectors and consequently force more fuel to the injectors rather than less. Return flow back to the tank is not my problem…rather it’s flow to the injectors that “appears” to be the problem. In fact…several years ago I had a 75 that was running real rough and I suspected a faulty pressure regulator. To check my suspicion…I pinched the fuel line at the tank return and the engine roared back to life and ran perfectly. Replaced the regulator and went on my merry way. So anyway...I appreciate your suggestions but I guess I'll have to keep looking. When I track it down...I'll let you know where it was. -SD