I have checked return lines. That was the first thing I checked when I fiquerd out I had a fuel psi problem. If 100 psi is normal I am starting to lean more to maybe a problem with the fuel distributor. I have a line on a used one. I am thinking maybe something is wrong with it not being able to hold fuel psi until the engine needs it. I am not familar with exactly how it works but I am guessing it should hold back some psi. I am ready to throw in the towel after that. I am undecided to either sell the car or take it to a local shop and throw more money at it. Its a clean car with only 87,000 miles but its just getting to expensive on the maintance. THANKS