A drop at the service port only tells you that there is a leak somewhere in the system, it does not tell you where the leak is. What was the pressure and leakdown at the fuel filter? Those readings, along with the service port readings, will tell where the leak is. Without both sets of readings, you're guessing, and guessing can get expensive

 

The specs at the fuel filter were within the service manual limits just don't have the numbers handy. The only drop I had was at the service port so Im guessing regulator or the spider. I guess I should just replace the whole spider since it has 200k miles.

 

What manual did you find the specs in?

 

It was the gm service manual. I have access to them at work.

 

Fuel pressure and leakdown specs, and testing procedures at the fuel filter, are not in the GM "dealer issue" shop manual. The link in post #9 explains.

 

I did have that information too and did follow everything, my mistake. Ive done so much work on her lately that it makes my head spin at times. After the front end rebuild, the engine removal and repair and now fighting the codes Ive had my fill lol.

 

I also forgot the new rear main seal leaking and being ripped off on craiglist for an engine. Its been a fun month for the blazer.