A few of you saw my posts over the past year(s) as to the progress of my daughter's wagon, which is a longterm junkyard restoration project. All your help was solid and needed and I thank you. The last and longest headache, however, was terrible surging and hesitation after running awhile. I tried everything: Wires, pumps, plugs, vacuum lines, mass air meters, relays. All the advice and the books led me in different directions. EVERYTHING was eliminated. The symptoms could originate from anywhere almost. I was so frustrated I ACTUALLY took it to a local mechanic who SAID he knew Volvos. Oh my!!! Now two weeks later and $700 poorer I finally went to this "Volvo expert" and got the car back. I stopped the bleeding from my wallet and he still charged me. Turns out he didn't know a cottonpikin thing and used the process of elimination like any old shadetree mechanic just like me. He replaced everthing I had already replaced. I will stop payment on that check and send him half what he charged me for NOT fixing it. I got that car back, took the pre-pump and sender out, took a bright flashlight and looked in that tank. UGH. RUST RUST RUST. I took the tank off. Easy job. I then went to a local PICK A PART yard and found a perfect tank off a '92 wagon for $45 and put everything back on. Put a bottle of Techron injector cleaner in there and a tank of gas and drove it hard for over an hour. It was perfect for the first time in a year. SOOOO, guys. Let my stupidity help some others. On those oldies, the problem may be even more basic than the pumps or injectors (which I almost but did not yet replace-whew!). Check out the tank! Water from condensation and sitting for long periods of time can cause bigtime problems with rust in those old steel (not stainless steel or galvanized)tanks. The rust and the grime it causes will plug up the pre-pump and cause the surging and hesitation once the tank pressure builds up and all that sedimentation sloshes around in the fuel. It is not wires, injectors, pumps, or vacuum lines. Look in that tank. If you drain it and the fuel is brown, PUT A CLEAN TANK ON and replace that sock on the pre-pump and maybe the pump too. And by the way, trust this board before trusting the local yokle mechanic.