I'm going to be about a month on the road relocating and living in my car until things get better. When I bought the 04 ss w/ 140k on it 6 months ago I had a blast with its ability to come out of a stoplight screaming and for several weeks just enjoyed the hell out of its quickness and all-around performance. I haven't enjoyed it for 3 months now. The night before she quit I got on it on a straightaway and she carried the mail. Ran it up to about 105 and didnt even really try, but I let off and drove normal the rest of the way home. That was it. The next morning I went to start it and there was a terrible shaking in the engine. I dont get it, how can something go wrong just sitting overnight? I had the shop read the code and the first was the MAF so I replaced it. Nothing, still bad, another code, TBS, nothing. It wont idle, stalls when I go to a stop or revs up and then dies. Up to 2000rpm, down to 200-300 rpm, barks the belt, recovers and up and down again, so I put it in neutral revving it to 2000 at a light so it wont die. Another code, idle control sensor, didnt change a damn thing. Another code, changed the EGR valve...freaking nothing. Pul the damn fuel pump and filter and change them out......nothing guys. When I put it in reverse or drive the engine rattles to beat hell. I had a vacuum leak at the fuel pressure regulator, it helped but still shakes. Had a fuel leak at a connector, replaced it, so now with all this stuff done it will idle for quite awhile then jump down and bark less often. I dont want it to run ok, I want it to run like its supposed too. It will get up to 40mph and then bogs with the deep low noise and then let up it smooths out. Whats left? 02 sensors, converter? Drop a 5.3 in it? Im getting ready to head out but I will have my computer but if its cold or hot I am not going to be able to set in the AC or heat because it wont idle. On the 04's is there a way since its all one piece to empty the converter and still drive it until I can get it replaced? Remember the old clutches in big trucks? If you didnt know how to usw a clutch the whole engine and drive train would shake and then die, that as close as I can get to describing whats going on. Thanks in advance for any advise.

 

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So here is a link for some of the issues you have identified.
You didn't say anything about a Fuel Pressure Regulator. I think I have seen where this has gone bad and then leaks and causes an explosion in the engine compartment.
It blows the plastic cover off and wreaks havoc.
something you might want to check out.

 

The off brand MAFs are usually worse than the OEM you just replaced.. I think more times than not you buy a MAF (not acdelco) and theyre bad. Actually, this goes for all the sensors on the throttle body.

Have you tried to unplug the MAF and see how the car runs?

Also, check that FPR. Like number3 said, itll blow that plenum to pieces. While the car is running, remove the vac line going to it and watch for a while. See if gas starts spitting out. It doesnt always spit it out so look closely to see if there is any gas coming out or even building up.

All the things you describe are exactly what happened to me the couple times I had a AIC valve go bad.

 

Not to be rude, but if you really plan to keep the car for awhile and even plan to live in it, I wouldn't suggest beating on it so hard once you get it fixed. Sounds like it'll be a pretty key part of your life, so you'd hate to have things keep breaking- especially something major like an engine or transmission from racing it around.

IMO you're coming at the diagnostic process from the wrong way. Rather than just replacing possible / related parts or just using the codes to identify things to replace, the codes should be used only as step 1 in the diagnostic process.

They were never intended to identify the component needing replacement, they're only to give you a starting point as to what system is exhibiting the issue and generally what the resulting fault is. From there, you're intended to go through the diagnostic tree to use other diagnsotic tools and data (OBD scan tool that can read sensor output, fuel pressure gage, multimeter, visual, etc) to determine which part is actually bad.


In terms of whats next - do you have a scan tool? Can you borrow one from a friend? Worst case you may have to buy a cheap one, but it'll still be cheaper than continuing to throw parts at it. Most of the other diagnostic stuff you can rent from Autozone if you find you need it for the diagnostic path you're on. Once you look at the data from the sensors, we can better help point you in the right direction. Otherwise we'll just be spit balling ideas.

No doubt a good mechanic who has worked on tons of a given platform can usually tell what's most likely to be the cause given a code, but for the average home mechanic with less experience (and where the parts are coming out of our personal pockets), its usually better to spend the time diagnosing the issue.



Sure, you can smash the guts to bits from the outlet side. It'll smell terrible and have a permanent check engine light. I think some newer 3800s have a cat test mode and can get a little wacky with the rear O2 reading a bad cat.

Before you did that though, I'd test to see if it is bad. An IR temp gun and vacuum gage should be able to give you a good idea.

The thing is that the guts are worth some decent money, so you'd hate to destroy them unless you absolutely had to in a pinch.