89 silverado running pig Rich

hello everyone, I have a a 89 1500 silverado with the 5.7 tbi, it was running good several months ago prolly mid late spring early summer its primarily a plow truck now. well after sitting a few months it now runs extremely rich lopes bad at idle like it has a cam clears out alil bit when you rev it but is growling and backfireing as it decelerates. its fireing on all 8 cylinders but all the plugs are getting soaked. The items I have gone threw with no success plugs and wires, temp sensor on intake, rebuilt the tbi, switched in a different maf and injectors I also inspected the vacuum lines for leaks any ideas from something i could have missed?

hello everyone, I have a a 89 1500 silverado with the 5.7 tbi, it was running good several months ago prolly mid late spring early summer its primarily a plow truck now. well after sitting a few months it now runs extremely rich lopes bad at idle like it has a cam clears out alil bit when you rev it but is growling and backfireing as it decelerates. its fireing on all 8 cylinders but all the plugs are getting soaked. The items I have gone threw with no success plugs and wires, temp sensor on intake, rebuilt the tbi, switched in a different maf and injectors I also inspected the vacuum lines for leaks any ideas from something i could have missed?

I'm not expert on this 89 tbi but If I owned it I would lookup the fuel pressure spec and see whats going into it ..I suspect too much pressure.

then a possible fuel venting system failure causing fuel to be sucked into the engine.

noticed something interesting today it looks like one of the braided lines coming from the tbi is collapsed the smaller one meaning the return line wonder if that could be it

noticed something interesting today it looks like one of the braided lines coming from the tbi is collapsed the smaller one meaning the return line wonder if that could be it

that is a good possibility...