Heres the deal:
Cold Start - no problem... ever.
Warm Start or after some driving - my idle will fluctuate at stops. Sometimes, if I slow down from a high rev fast enough, my RPMs just drop right off the tach and I stall. I have to double foot it at stops when the engine has been running for some time. Heres the weird things:
1) After driving for some time, I can put in in park, rev the engine and get it to stall.
2) Sometimes I'll just stall if I sit at stop for a while, whether in gear, neutral or park.
3) I have the hardest time starting the car after a stall. I will literally sit wherever (and it has been some bad places) for up to 20 seconds cranking the engine to get it to start. 20 seconds may not be that big of a deal but it can be bad when your on the side of an on-ramp to an expressway.
4) When I finally get some juice after cranking, I get TONS of smoke. I have to then keep my foot on the gas and shift into gear or it will stall. This is gonna kill my tranny.
5) Gas Milage is absolutely HORRIBLE!!! (7.5 mpg avg fuel econ!)
6) I get a HORRIBLE gas smell in my cabin afterwards. Its real strong too-- definately gas.
7) Code 44 was set on my computer. I just checked it today. Too Lean?
I am so puzzled by this-- It's like a combination of problems I've read on here... any help would be GREATLY appreciated.
I'm not just running a basically stock engine, only did a air filter mod to remove the stock air box.
Do you press the gas pedal at all during the 20 seconds when you're trying to get her running again? If so, then the smoke is normal because you have flooded the motor, and it's burning off the excess fuel. As for it stalling, I would say to check the IAC or try unplugging the EGR next time this happens. But the whole horrible fuel economy wouldn't have anything to do with the above problems, I don't think. Does it feel slow at all durning normal driving, like it takes a harder press of the accelerator to get it moving? If so, your fuel pump may be on its way out, possibly even a clogged fuel filter. I'd also check the fuel regulator and the injectors. Perhaps even the ignition module. If you're showing lean, somehow you're not getting enough fuel to the engine compartment. The only reason you can smell gas so strong after you get her started again is because, like I said, you've most likely flooded the engine.
Sounds to me like you have a classic "cracked Cross-over" to me. Do you have a Jeff M cross-over or the stock cross-over? In case you don't know what a cross-over is...in lamens terms it is the exhaust pipe the brings the front and rear bank exhaust manifolds to the turbo. In the piping there are two bellows that expand and contract with the heat generated during normal use. The metal used in the stock bellows is very thin and not very durable.
With a cracked cross-over...you will get a false lean condition if the cross-over is cracked as it is sucking in fresh air and the 02 sensor sees lean air...the ECM will then correct for the Lean condition with much more fuel that is not needed fouling out your plugs and causing the stall. Irratic idle will also persist as there is entirely too much fuel in the cumbustion chamber.
You should contact Jeff M for more troubleshooting to isolate it to the cross-over... 8)
I am still using the stock crossover. I had a stalling problem before, and I attempted to learn my idle using the instructions on http://www.60degreev6.com/index.php?p=pages&pid=74 and that seemed to work for sometime. However now I can't even relearn it without the car stalling. Thanks
The stock cross-over is most likely the reason you are having the issues you are speaking of. Jeff may also want you to check the fuel pressure regulator...but I am 90% sure with the symptoms you have discribed it is your cross-over. Jeff builds an updated and high quality cross-over replacement that is a fraction of the cost that GM wants and it is the same exact weak cross-over that you are having problems with now.
Look here for what your X-over looks like. http://www.netavalanche.com/tgp/viewtopic.php?t=1509
idbeast or Chris A...anything else he may want to look at first? 8)
The cross over would cause it to stall? I thought it would cause some driveability issues, but I didn't think it would cause problems at a stand still.
Yep it sure can cause stalling issues. Since your gas mileage is bad I would second the crossover issue. The car THINKS its lean because its suck in air from the cracks in the crossover and adds more fuel. This excess fuel can be so bad it floods the motor out and causes it to stall. After it runs this way for a while, the o2 sensor will go bad and things will really get out of whack. At 7.5 mpg (is this calculated or what the trip computer says?) you are really dumping in the gas.
Other than that, it could be the idle needs to relearn if you've had the battery disconnected recently.
Have not been able to read let alone post on the boards but thought I should see just how many weeks I have missed. It is great to see so many guys laying down the info to help and covering all the bases, there was a time when there were not many at all who knew these vehicles, we kick butt now!
Easy to check what has been said and is common as well as typical of your problems, the Fuel Pressure Regulator/FPR! Look at the top of the throttle body, find the hard plastic vacuum line closest to you/first one, follow it down to just under the upper intake manifold, it turns into a rubber ?T?. The end of the rubber ?T? goes into the top of the FPR, remove the ?T? from the FPR, attach another vacuum line to the FPR and suck on the end of the vacuum line to check if the FPR diaphragm is leaking, if it does not hold a vacuum then its bad. Rich running from this FPR and a cracked crossover pipe can take out a cat too so glad to hear you are taking care of this. This FPR is common but I have dealt via many emails with engine running problems that can be as out there as far as you can dream/nightmare :crazyeyes: , with previous owners/garages putting in smaller injectors to correct rich fueling/stall problem from a stock/cracked crossover and/or bad FPR, and on to mixed sized injectors (some stock 22lb some not), then swapping the ECM but forgetting to swap the TGP chip, lower intake manifold vacuum leaks, stalling only when having the brakes on, EGR and canister purge lines taken off, EGR metal tube leaking and the leaking exhaust melting the vacuum lines under the lower intake, the list goes on but just some background is to leave nothing to chance so?.look at everything and make sure there is nothing out of place or odd, look closely at an engine pic of a good running TGP, study the running of vacuum lines, wires (Spark plug wires too, just had a high idle rpm problem/dead battery caused by one spark plug wire wearing into the + batt post of the alternator!), connections, hoses etc. Best of luck, just know it ran good when new and can get there again and these guys rule here in helping you out 8) !
Jeff M