I've been fighting this problem for a while and I was wondering if I should be looking towards the opti or not. In damp weather, if the car has been sitting a while, it doesn't start. I dont believe its firing. If I crank the car for a while and hold the pedal to the floor (so it doesn't flood), eventually I get it to fire and it runs rough for a couple min. then its fine. After its been driven a few miles it'll fire up every time until I let it set for a long time again. Last night was the worst; pouring rain and it took almost five minutes to get it to fire. I'm starting to get pissed. Does this sound like opti related?

 

Yup. Or maybe a frayed plug wires that is getting wet?

 

I am actually having this exact problem right now with my 95 z28 a4. I was thinking that it was an opti related problem and also would be interested in any input you guys might have on this problem. Thanks.

 

You may want to check under the hood the next time it rains. Water can run over the rear plugs from the top of the firewall/cowl. There is an ~inch wide piece of piece of weather stripping between the front edge of the plastic cowl and the sheet metal under it. Needs to be there to keep the water off the block.
Doug

 

Could be the check valve in your fuel pump. If the fuel system doesn't hold pressure during starting, it makes for hard starting. Connect a fuel pressure gauge to the Schrader valve on the fuel rail and measure the fuel pressure when you turn the key to run, not start. The fuel pump should prime for 2 seconds, the pressure should come up to around 35 psi and then hold steady when the fuel pump shuts off. If the fuel pressure drops off quickly you most likely have a dirty/failed check valve (common failure). It could also be a leaky fuel pressure regulator, leaky fuel injector(s) or a hole in the fuel line.

 

Hey did you ever find the problem. My car is doing the same thing. Funny thing though, I have put an LT1 in my 90 silverado and it is doing the same thing. The LT1 in the truck has a new opti in it so I am pretty sure that is not the problem.

 

My 94 is doing the same thing but it will do it no matter what type of weather it is. I believe it is my check valve. It will start for me if it doesnt sit long but if it sits for a while it takes a good 5-10 sec for it to start.