86 Iroc Z. SD 355 Superram. Surging idle, dies when you put it in gera. etc. It idles great until it goes into closed loop. Any suggestions? I have replaced fuel filter, adjusted IAC, TPS, spark is steady, fp is steady, seams to have no vacuum leaks.


Thanks

Chris

 

sounds like it could be the o2. I'd throw a scan tool or a volt meter on it to be sure.

 

scan tool is showing that it is working, stays between 126-132 even at idle(if you can call it that)

Chris

 

From what I've read, if the car is sluggish it is most likely ignition, fuel, or a sensor. Looks like you've ruled everything else out. I had the same problem last week and the O2 did the trick.

 

What stays at 126-132? Your oxygen sensor voltage should constantly fluctuate above and below .5 volts.

 

Sorry, was referring to the o2 block learn.

Undid O2, still doing the same thing. New(cleaned plugs) same thing. So here is a new list of things I have ruled out

-plugs(cleaned)
-tps(adjusted and working correctly)
-iac(adjusted and working correctly
-fuel filter(replaced)
-fuel pressure(verified)
-o2 sensor(unplugged/same symptoms)
-vacuum leaks(none found or heard)


Next I guess I will have to pull the superram after I try a pressurized fuel injector cleaner(professional grade). Any more suggestions??


Chris

 

Auto? Sounds like a torq converter not unlocking or locking prematurely. I'd suspect the tranny. Next time it does it, quickly put the car in neutral. If it smoothes out, the tranny is probably at fault. Makes sense to me.

 

It also surges in nuetral and we have a lot of gas in the plenum. We think it may be a suspect injector. Off comes the superram. Anymore suggestions, opinions.

Chris

 

possible faulty collent sensor . Had a cracked one on a 88 TBI motor in a truck ...... ran really rich( high gas smell ) , stumbled after a while of driveing ........


something else to check

 

so wait... you unhooked the oxygen sensor and nothing changed. It sounds like it could still be an oxygen sensor issue to me. If your oxygen sensor is FUBAR, unplugging it won't cause the condition to change.