bought car in non running condition was told opti was bad replaced it car starts fine but after 2 minutes starts missing on random cyl apperently has been a problem for other guy too it has what looks to relatively new reman pcm and this is the second opti along with cran sensor and a bunch of other stuff also i noticed on both post cat o2s unplugged and some little device plugged into harness what the hell is going on

 

I would scan for codes first. If you have post cat o2's your car is obd11 and auto zone can scan if you dont have access to a scanner.

 

The "little devices" are O2 simulators, or "sims". They fool the PCM into thinking the cats are still there, to prevent SES light/codes. Appears your catalytic converters have been deleted.

Starting and running fine for the first few minutes, then missing when it goes into closed loop would indicate a possible problem with the pre-cat O2 sensors, or a false lean condition that causes excessive long term fuel corrections by the PCM.

Appears your car is a 96/97, so the PCM can collect the misfire count by individual cylinder. A scan, using a scanner with GM "enhanced parameters" can access the misfire counts, which may point you to a specific cylinder, pair of cylinders, etc.

What is a "cran sensor"? Do you mean crank sensor? That's just there to help detect misfires. Doesn't affect how the engine runs. What code(s) were you getting for the crank sensor?

 

Would not expect it to go into closed loop in only 2 minutes from dead cold. Please confirm it's a closed loop issue. If you don't have a real time scanner then unplug an O2 and see if it runs better.

 

got the codes p0131,p0161andp0300 so i should try to fix the 02 sensor problem first also i think the vacum lines are hooked correctly but not much vacum at intake boot like possibly a leak in opti sorry about this but im a severe duty truck tech so ingnition systems are not my friend

 

If by "intake boot" you mean the rubber bellows in front of the throttle body, there wouldn't be any vacuum at that point (unless your air filter is extremely dirty). Vacuum builds behind the throttle plates, not in front of them. The line that connects there and runs to the Opti supplies air from the bellows to the Opti. Opti vacuum is pulled by the line that connects to the driver's side of the intake manifold.

P0131 = Driver's side pre-cat sensor stuck at low voltage (less than 200mV). That would either indicate the driver's bank of the engine is running extremely lean, you have a large exhaust leak on that side before the O2 sensor, a vacuum leak that only affects that side, that bank of the engine is misfiring excessively, an injector is not working, the O2 sensor is shorted to ground, etc. This is the primary issue that is causing your problems. Switch the two pre-cat O2 sensors side-to-side. If the problem follows the sensor, its a sensor problem. If the problem stays on the driver's side, the sensor is OK.

P0161 = The heater circuit in the passenger side, after-cat sensor is not working, based on excessive time for the sensor to start working. Since there appears to be a "sim" in place of the O2 sensor, the sim or the harness connector is probably defective. But this code will not cause the engine to run poorly.

Does the car have headers?

At this point, you have to list the basic info for the car - you should add a "signature" that includes year, model, engine, trans and any major modifications.

 

on the vacum issue i have larger port on opti connected to intake so i get full vacum there so if i pull the other hose from the opti to intake boot should i not get vacum there also. and on the injector not functioning im watching with a snap on scanner so i can see the missfire bouncing around cylinders but i will get o2s fixed firt then repost sorry about lack of info theres just to much wrong with this thing to list

 

Excessive vacuum to the Opti can deform the case. The stock hose has a flow restriction orifice to prevent excessive vacuum, and a check valve to prevent back-pressure in the event of an intake manifold "pop".

The lines should be hooked up like this (courtesy of Shoebox):

http://shbox.com/1/opti_vacuum_harness.jpg

You said you had no vacuum "at the intake boot". My response addressed the absence of vacuum at that point IN THE BOOT (BELLOWS). Now it appears you are asking if you should feel vacuum at the end of the air supply hose, attached to the Opti. Yes, you should. But as noted, there is a device that limits flow through the system (again, from Shoebox):

http://shbox.com/1/opti_vacuum_hose.jpg

Its always difficult reading and interpreting a post with little or no punctuation or sentence structure. And I wasn't asking for a list of what is wrong... I was asking for a list of the basic data for the engine.