engine miss at low rpms under low

[zpyro]

engine miss at low rpms under load

that's "under load" not "under low"

I just picked up a '90 sho, and after replacing the clutch (toasted) and the plugs (cheapass champions, replaced with Motorcrafts), the engine still runs like ass if I'm in, for example, 2nd gear, and give it any more than 1/4 throttle. after about 3-4k rpms it clears up. any ideas?
I also ran some seafoam through it and it didnt make much of a difference.

also, when i had the hood open and was finding a suitable vac line for the seafoam, i noticed a small vacuum hose was sitting there leaking vacuum. it's coming from some solenoid-looking thing, behind the engine (firewall side), has about 7" of line, then a T fitting, then about 7" more vac line. I couldn't find anything missing a vac line so i just put the loose end on the T

 

[zpyro]

ran the KOEO test, got nothin (11). ran KOER, got 41, 91, and I think 13 (might have misinterpreted it). IIRC and if the codes are the same as my stang was, 41 and 91 are the O2 sensors, right and left bank. is that true? would they cause it to run like it does? i've yet to get under the car, are they a PITA to get to? and im sure they dont supply you with **** when they rape you on the cost of em...

 

[Fourcats]

We found the plug wires to be at fault...

 

[zpyro]

so the codes dont mean the o2s are bad?

 

[zpyro]

anybody? anyone know what that vac line is for? I can't find anything on the manifold where they would go...

 

[jedhead]

The codes mean that the O2 sensors are reading a lean condition. There are so many vacumn lines I can't begin to guess without pictures.

Bob

 

[zpyro]

so I'm thinking the secondaries are staying open, because they dont have any vacuum to keep them closed? WOT=no vacuum right? and when it finally gets to when the secondaries are SUPPOSED to be open, the computer kicks in the extra fuel to richen it up. I read that the secondaries open at about 3900rpm? that's when the choppiness clears up..

 

[Fourcats]

If you go to the "AutoZone" site there is a section on Vacuum, with diagrams. I recently mounted a vacuum gage, thinking there was a leak. It shows 17in cold and 21in hot , the problem is looking like the smog paraphernalia on the engine.

 

[zpyro]

K I think I got it...I for some reason had a vacuum line going directly from one secondary to the other. I was wondering how the **** they'd open if there was no vacuum source. anyways, I took that loose vac line, put the loose end on one secondary and that aforementioned vac line between the secondaries and connected it to the T in the line. it no longer chugs from a stop, but it still kinda does if I floor it in 2nd at low rpms..

oh and the loose line was coming from a solenoid, which had a vac line coming from that little round thing that goes into the clip on the backside of the intake, and a vac line goes from there to a vac port on the intake. so it seems I was right w00t