drperformance

iTrader: (5)

Ok, I cant figure it out I am getting no codes, but the car runs like ***. It seems like the car is being starved for fuel or being flooded with fuel. It sucks down gas reel fast (which leads me to think rich) and stumbles or misses at every speed. It ran good for a day when I unplugged the o2 sensors and kept the car in open loop, and then the next day the car developed the same problem in open loop? A while back I also had a problem with the idle surging but it cleared up when I cleared the tps code? And then it started surging again with no code and the quit and started to miss or stumple (where this problem started)?????

I replaced the o2 sensors and bought the extentions instead of extending them my self again. And I also tried a new map sensor.

Here are the readings from a snap on scanner at idle, park, and in closed loop!

left o2-230(bouncing)
right o2-230(bouncing)
left blm-111
right blm-132
A/F learned-yes
ft cell-16
tps(v)-.76
throttle-0
left bpw-3.4
right bpw-4.2
air flow-11
iac position-77
coolant-85 c
mat(c)-58
fan 1- yes
fan 2-no
map(kpa)-50
map(v)-2.18
baro(kpa)-97
baro(v)-4.70
knock-no
knock retard-0
spark advance-28
ignition(v)-12.9
ccp duty cycle-0
egr-0(programed out)
desired idle-850
tcc command-p1
tcc brake signal-closed
veh speed-0

I also scanned the tranny with no codes!

Any help would be awsome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

1991 RS/SS

Not knowing wht is right or wrong for most of the values you listed, I am ignoring them and going on a hunch (from experience) - bad optispark

Also, I have heard that LT1 engines want a idle TPS voltage of .7 or so, but I have also heard .6 is that max you want. I dont know which figure is wrong, but I know mine starts running bad when it gets above .62 volts. (this may or may not have anything to do with your problem, but I figured id throw it out there).

Now, I cant say for sure that the opti is the problem. I was having issues similar to yours, and I replaced O2, maf, map, tps, ign module, plugs and wires trying to find the problem (as I had no codes either) and the map sensor seemed to make things alot better when it was replaced. This year I replaced the opti for peace of mind and it now runs 100x better. My old one had about 80,000 miles on it. I replaced it with a new GM one as I didnt have time to wait for the MSD one.

Good luck.

Klortho

Map value looks kinda high, I checked a datalog on mine and it's sitting on 31kpa...BPW's look high as well, which could be dumping a tad more fuel in than needed, BPW's on my stock setup at idle are 2.52 and 2.93...what do the O2's bounce from and to? Mine go from about 260 to 900 IAC looks sort of high as well at 77, most of the ones I've seen are around 40

Firebat

iTrader: (7)

try taking off the IAC and cleaning it with carb cleaner. A high MAP value means vacuum leak or too much air coming in somewhere. Try adjusting the throttle stop screw on the throttle body too - maybe your throttle body blades are open too far(but if that was the case your IAC would be very low). I dont know for sure, try those 2 things first. And also look for any vacuum leaks. Another thing that's common is the connector for the map just goes to crap. If the tab is broken off, then replace that connector. Could be a bad map sensor too, highly unlikely, but i've had to replace my map sensor.

Is this a stock engine? Map values for stock will be around 30 kpa. I think with bigger cams, you expect a higher map value.

What about fuel pressure?

drperformance

iTrader: (5)

Ok the lt1 is not stock! I have an lt1 hot cam kit in it and hade the heads ported, polished, and a 3 angle valve job. I also had the intake ported and polished, and I have about every bolt on. The map sensor is brand new along with the o2 sensors (NGK Brand) and they bounce to about 900 or so. I have a 32 millimeter holly throttle body and thought that the blade stop screw came in the stock place or how would the stop screw effect a miss or stumble? And I put a k&n air intake on it, and it sounds like the intake or throttle body is very loud (loud sucking noise)? And I also bin over the engine multiple times with carb cleaner and foumd no vacuum leak. And the IAC valve looded clean when I removed it.

I also tried a snap on vantage scanner, which tests each sensor individualy (by manualy tapping into them) and the all look to be good or have good values.

THIS IS DRIVING ME CRAZY!!!!!!!!!!!!!!!

Firebat

iTrader: (7)

Sometimes the MAF gets dirty from K&N oil and causes the airflow readings to be way off. And the MAF is only used in closed loop. To clean a dirty MAF, clean the MAF with rubbing alcohol and a q tip.