surging at lower RPMs

[Oz]

Going off topic here... 

Back to the original issue, "surging at low rpms" please.

[Eyez Open]

I just love oil threads, they can be a bad as politics! RV engines are high heat severe duty cycle engines, they do not loaf around in the same manner as an auto engine. My personal favorite would be Rotella t4, I've used it in marine engines for many yrs and some very high powered spendy engine's. Right now it is being cleared out and it is dirt cheap...https://www.walmart.com/ip/Shell-Rotella-T4-Triple-Protection-SAE-15W-40-Engine-Oil/181236405?wmlspartner=wlpa&selectedSellerId=0&&adid=22222222227055967879&wl0=&wl1=g&wl2=c&wl3=159472094864&wl4=pla-267896677850&wl5=9032828&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=online&wl12=181236405&veh=sem&gclid=CjwKCAjw49qKBhAoEiwAHQVTo-yg06qDrPN0QL3tkbFmLtL1zPpHuYAOYvskW0ZgQ8dhhAjwQlQ5jhoCpLcQAvD_BwE&gclsrc=aw.ds

Ok, where were we...Oh yes, idle surge..and one-note. The original poster has a roller cam that does not need high Zinc additives. Flat tappet cam are the needy bunch, carbed in general have flat tappet cams...Peace out.

[JonnyG]

I'm bad for getting off track, there is so much to cover. Maybe what I should have asked is for tuneup tips as this so quickly turned into far more than just the idle surge.

Thanks for that tidbit about the zinc additives, too much reading can cause some confusion as I'm starting to realize.

I just did an oil change to mobile1 extended performance 5w30, seems to run smoother and less vibrations. I'll have a better idea once I can take it on to the highway. Making progress non the less

Would an exhaust leak happen to cause any of the surging or lumpiness I've been describing?

[eXodus]

exhaust leaks should not cause surging, - only when the O2 sensors are involved.

Should be still addressed if you got some.

When you ruled out all Vacuum leaks you might going down and change the the O2 sensors. At 40.000 miles they should be still fine.
But maybe whatever causing the surging - has damaged them.

for testing you can just move the pre-catalytic converter sensors to after the converter and vice-versa (if they are the same, depends on year)
The pre cat are usually the ones which get the brunt. 

Since you apparently had a misfire from those ignition wires - the O2 sensors potentially be fouled with unburned fuel

[udidwht]

A 1994 454 TBI will have a mild hydraulic lifter cam in it not a roller cam. As for oil user preference. I use Mobil 1 Extended Perf 10w-30 or Valvoline VR-1 Racing 10w-30

Iridium plugs are best suited for coil over ignition systems. Copper plugs are best suited for these engines but one can use Platinum plug for an extended interval. I generally use either AC Delco or Autolite Copper plugs and run them 25-30K. The 94 & 95 year 454 TBI had 26-32 psi fuel pressure.