98 5.7 vortec fuel problem?

[stevenmc08]

Truck has 160k, new delco plugs, wires, and the intake gaskets have been replaced.

Symptoms: rough idle, when its cold it turns over a while before it fires, and has a loss of power. It also rarely will downshift pulling hills unless you make it. My cel don't work so I don't know if it has any codes, but plan on getting the codes read tomorrow if it has any. I'm leaning toward the spider system needs replacing but want some ideas first. This is my first vortec 350 and don't know much about them since I've only had tbi 350s. Thanks in advance!

 

[bluex]

Check your fuel pressure an how long it keeps pressure after you cut it off.

How old is the cap an rotor

 

[stevenmc08]

I'll have to look at the receipt and see if it was changed with the plugs. I just got the truck from the original owner and he said its always idled rough as long as he could remember. He had just had the plugs and wires done before I bought it so if it was changed then its only a couple months old. Where should I hook the gauge up at before the filter?

 

[shorepatrol]

Top driver side rear of the manifold is your service port to check fuel pressure

 

[stevenmc08]

I got the codes read today but haven't got to check fuel pressure yet. Codes are cylinder #5 misfire and bank 1 sensor 1 O2 sensor. It had plugs, wires, and dizzy cap replaced in October. Y'all still think it could be fuel related?

 

[Toyojake]

Based off of what I've been reading and the similar issues in my 2000 350, I'd be looking at the spider injector assy. Pretty sure thats what's leaking and causing my problems...just haven't changed it yet.

 

[stevenmc08]

Wouldn't it cause a random misfire code rather than just cylinder 5 if it was the spider assembly?

 

[Toyojake]

Wouldn't it cause a random misfire code rather than just cylinder 5 if it was the spider assembly?

I don't necessarily think so, if it is just that poppet valve that is stuck or damaged.

 

[SAATR]

What exactly was the O2 code?

 

[stevenmc08]

What exactly was the O2 code?

They never told me. Just said bank 1 sensor 1. I put a cap and rotor on today also and has helped cleared it up some. It does it on start up and very very little at idle now. I'm gonna replace the o2 tomorrow and if that don't work I'm gonna try to find a tech II or snap on scanner to dig a little further. Could that O2 cause some of the problems? I also forgot it has an exhaust leak at the flange right after the cats. That shouldn't affect anything since its after the cats right?