So I have an 89 350 TPI. I have always had the usual bit of a stumble problem from idle up to about 2000 rpm when the car is cold. 5 mins of driving would usually take care of that. Well yesterday, I went out to the garage to start it for a while like I usually do during winter, and it took forever to get it going. Once I finally got it fired up, it would not stay running unless i kept reving it. I got a code and it was code 44 (02 sensor indicated lean for more than 50 secs in closed loop). After retrieving the code I tried to start it again and it was much beter. Started and actually idled by itself but if I went near the gas pedal it would try to die out. Timing is fine, fuel injectors and sensors all have less than 6000 miles on them.( MAF, CTS, 02, EGR, ETC.) Fuel pressure is at about 42. The best way I can relate these symptoms is to a carbed engine which is choked out. It idles fine but stutters and stumbles when I hit the gas. But if I slowly fight it up to about 2000 rpm it runs smooth. We had a few below zero days here in chicago so I wonder if it could be as simple as a frozen fuel line? Thanks for any help in advance guys. What else should I check?

IAT= intake air temerature sensor. If you access to winALDL check what it's reading. It may be telling the ECM the air is 90° when it's freezing cold.
Spark plug gap and ignition voltage at plugs. Should jump a 3/4" gap with a loud snap.
Frozen fuel line should give "cranks then dies" symptom or no start. If any of your gas is "ethanol-enriched" (I hate that term), any water will be removed with a tank or two.
Anybody want a "tax-enriched" paycheck?
...a "bite-enriched" hamburger?
...a "purchase-enriched" credit card statement?
..."rash-enriched" skin?
...an "STD-enriched" girlfriend?
Gimme a break.
Here's an idea: how 'bout put some F****in' gas in gasoline.
(sorry about the rant. guess I'll have an "ethanol-enriched" malt beverage)

LOL!!!

But seriously, (yeah, right....) it is all a marketing ploy. After all, it is not like alcohol makes it a better fuel... Consider though, if they called it "Ethanol Polluted" do you think folks would still buy it?

Thanks for the ideas. What is winALDL? I'm guessing it's a diagnostic reading a step or 2 above the good ol' paper clip and blinking light? Lol about the frozen fuel thing, at first it was "run for 5 seconds, then die" unless I kept reving it and reving it. I also forgot to mention that I just switched over to stainless braided fuel line and -AN fittings. However, the car was running fine for 2 months after I did that and now this just came up from nowhere. I will check the IAT but i'm pretty sure I replaced that too. Any more ideas guys?

Anybody?

WinALDL is diagnostic program you can run on a laptop with a cable connected to the ALDL connector that will show real-time data from the ECM.
If the car is still doing it, you can check the fuel pressure while it's misbehaving. If it's from ice in the fuel lines, pressure will be low while it's running. This will eliminate the fuel supply as one of the possibilities.

Please note, however, that the computer has no clue what the fuel pressure is, only way to tell is a mechanical gauge, screwed onto the test port.

Thanks guys. I did a search on winaldl and found a very good site. Do you guys use it? Is it going to jack up my laptop? I don't want to be out 2 grand if it's not safe. Being as it is 3 degrees here in chicago, it would be much easier to be able to read the sensors rather than remove and test each one. Thanks again guys. Anyone else?

bump

Perfectly safe. Browsing the DIY Prom board will show that many folks use it, without problems. Besides, no software can really screw up your computer, there is always the wipe, and reload option....

Cool sounds good. I know everyone says it is easy to build a cable, and i'm sure it is (i am pretty handy with a soldering iron), but every diagram and schematic i see seems very complicated. I don't even know what parts a would need. Anyone know of an idiot proof schematic?

anyone?

Have you done sparkplugs, wires, cap, and rotor?

Yea all new accel ignition parts. Rapid fire plugs, wires, coil, and the notorius DOA ignition control module replacement all have less than 5000 miles. I only drive the car in summer so it doesn't get too many miles and i have been driving it for 2 years since the restoration. I'm beginning to think it's just the extremely cold weather we have been having in chicago. I also did the throttle body coolant bypass and wonder if it is having an effect in the cold.

Did you ever figure this out - I have the exact same problem.

Bumping a year old thread, and providing no information on what you have tried to solve the problem isn't going to help you. Start your own thread, give detailed information on your car, and what you have done so far, and you will be much further ahead.