Spark plugs and other engine questions

[Yenkohead]

Hi everyone. Well, the saga continues. I removed all of the plugs (AC-Delco 4I-906). They all looked very good. I gapped them all to .050. Fired it up and there was no change (maybe a little worse now). Review: Idle pretty rough (I wish it was because it had a radical cam, but no) - kind of choppy and inconsistent. Was thinking bad gas - but haven't driven it enough to use up the tank - hope to fill up with 93/94 Sunoco soon - addition of some old octane boost made no difference. Any "heavy pedal" and there is pinging under load. So I checked for arcing last night (idling in the dark) and noted what I initially thought was arcing but upon closer inspection it looked like the porcelain was just lighting up for about 5 of the 8 plugs that I could see from the top. I don't think the porcelain is cracked but I guess anything is possible. I am going to go ahead and get some new plugs but would like some advice on what to get. I have seen reference to Autolite 103/104, NGK TR55, Bosch BP???, AC-Delco (Rapidfires?), and maybe some others. In my case, I have a mildly built '93 LT1 block with a '94 ecm, intake, etc. At one time it ran great. Suddenly it has developed this weird idle and pinging under load. The fact that the plugs all looked pretty good (light tan and no evidence of buildup) leads me to believe I can rule them out. So, after replacing the plugs, what would be the next logical place to check. Oh yeah, I am getting no codes or SES.

Thanks,
Greg

[popo8]

Lets go back to the beginning...

Have u checked fuel pressure?

[Yenkohead]

Lets go back to the beginning...

Have u checked fuel pressure?

Actually I haven't but hope to check it tonight. Intend to remove and inspect the fuel filter first. I went ahead and picked up some Rapidfire #14s today as well.................just in case.

Thanks.

Greg

[popo8]

Ok... let us know what u find. Back to baby steps and we will figure it out.

[Yenkohead]

Lets go back to the beginning...

Have u checked fuel pressure?

I just checked it:

Key off = 0psi
Key on = 38psi
Engine on = 37psi
Higher rpms = 35psi

Heading next to the injectors and fuel filter. Will report back later.

Greg

[englundjd]

that psi seems pretty low. it should be around the high 30's at idle and 43+ at wot. your looking at a fuel filter and if that doesn't help a pump maybe in your future, filter first tho cause there cheaper

[Sahara54]

How fast does the pressure bleed down after you turn the key off. It should hold pressure for quite some time.