I have a leaking spider injector.. can I just pull out the O rings and replace them....or do I need to order a new spider...thx for any inputs

 

I'm no mechanic but I've been chasing miss issue on my 98 and from what I've read and seen first hand; its not a seal thats leaking; its that carbon gums up those poppets and they either dont open or they get stuck open thus leaking fuel.

Its best to replace the entire thing with the upgraded Multifuel version that swaps the poppets for mini injectors. I did mine; super easy .. got one for under 300 bucks from Rockauto and is ACDelco brand.

 

If you're capable of pulling off the intake plenum (as you suggest) then look at the old spider. If there is a "clean spot" under the Fuel Pressure Regulator (FPR) you may be able to get off cheaply by just replacing that part because that is where your leak is. If there are other spots in the intake that have been "washed" by raw fuel, you should bite the bullet and replace the entire spider with a new style Multi-port Fuel Injector (MFI). It will be worth it. Also, pop off the throttle body (TB) (3 bolts plus the throttle bracket) and clean it good with a soft bristle brush and carb cleaner. The gasket can be reused but a new TB gasket comes with the intake plenum kit (Fel Pro MS90269) I went to a pick-a-part salvage and took off a plenum just for practice. Was pleasantly surprised to find a new style MFI spider under it! Bought it for $40 and installed it in my Suburban. Fantastic improvement! The truck was fresh in the yard so it had not sat for months/years. The used part worked great.

 

Replaced my spider injector with AC Delco upgrade "MFI" also did timing chain though the one in there was fairly new... did see an improvement on how it was dumping fuel exaust was not so 'chevy' if you know what i mean cleaned the gunk out there too the best i could... a few of them mainly up front (where most of the gunk was) were just about ready to clog up as it looked...

I really did not start getting better running till i replaced TPS (Mine didnt have spring action and was really worn) that helped alot.. then i replaced MAP sensor that seemed to help alot.. still have miss but no where near what i was having P300 , now im getting actual misfire for #4 cyl which is one that i have non-fouler on for oil, thought it was valve guide seal... might be intake based on symptom.. cold engine it will miss but once warmed up it will not miss or harndly noticbile.. get on highway it will have random miss (Cyl 4) at higher speeed crusiing as if the vac.. is sucking in oil or something thats my thought.. thats my next project pulling the entire intake out.. wish i would have done when doing everything else..