BG Auto: Need help pinpointing car problem

[Corrderio]

Hey BG, I'm hoping one someone here is a mechanic or has automotive knowledge since I'm in need of some assistance.

Before I start, I want to make two things clear: I have pretty much no knowledge about cars, so I don't think I can help much in trying to look around under the hood. And my car in question is a 2003 Chevy Trailblazer.

Anyway, with that out of the way, the problem.

Some time in late March my car's engine suddenly up and died on me without warning while I was sitting at a red. I couldn't do anything but put my car in park, turn the ignition off, then turn it on again to start up the motor. After this I got myself an appointment with a nearby mechanic as early as I could and told them about what happened that day and how it might have been possibly connected to an earlier incident when my Service Engine light came on (I can't fully remember the details, but I think it was something about the connectors on the battery not having a good charge and they cleaned them). They called me later in the day and told me they took my car for a test drive and had it hooked up to their computer system for any abnormal readings but said they couldn't detect anything. So instead they fucked me over by saying my spark plugs were close to being due to be replaced and had to replace my coils to since one was corroded. Long story short, 910 bucks down the drain.

Now jump to earlier today as I was heading home. I was stuck at a light again and as I was turning to make a left my engine once again decided to crap out on me with the same story: couldn't do anything but place it in park, turn off ignition, start ignition again. So the 910 I spent didn't really do anything but bleed my wallet dry for a bit and confirm the problem is still there. So now I'm curious as to what the problem could be and I was hoping some BG users who are experienced with automotive problems might have an idea on what the problem could be.

Thanks in advance.

[Sanjurio]

Is it overheating? Did you notice it idling/reving high/erratically before it died?

[Aragon of Odin]

Could be your fuel pump, Trailblazers/Envoys have a shitty ass fuel system that are always causing problems. I've had two Trailblazers and had to do the fuel pump on both of them, and of course with their shitty ass design you're looking at $1200+ if it is the pump. This is just my experience though, I'm no mechanic, though I do have some understanding of cars. I had the exact same thing happed with my Caravan this year, and again it was the fuel system, though warranty covered it at least lol

[Zeb]

I was also going to suggest fuel pump problem.

[Acevalefor]

Possibly a cam/crank position sensor. My wife's ford windstar started out the exact same way when the camshaft position sensor started going bad. Eventually, it got to where it would not idle at all and took 2 or 3 tries to start.

If it is not a sensor, it could very well be the fuel pump. Does it feel like you have less power than you used to, or does it bog down on hills? If so, more likely fuel related than electronics.

[Corrderio]

Is it overheating? Did you notice it idling/reving high/erratically before it died?

Now that you mention it I think it does rev some times. Don't think it's overheating in any way though.

@Acevalefor: I haven't noticed anything of the sort when I go down hill.

[Sanjurio]

I just thought of something, is the key you were using chipped? I don't know about Chevy, but my 01 Jeep has a chipped key and if that chip goes bad it can cause a problem like the one you're dealing with too.

[elison]

Did you ever get anyone to tell you what the Service Engine Soon light codes were? Autozone will check them for you for free. When you get up in the morning and go to start the car, does it start without problem or does it take a while? How long after you first start the vehicle and begin to drive it does it die? The fact that it's dying while driving eliminates a lot of what was suggested above.

Ace is pretty close, could be a faulty cam or crank sensor. More so crank sensor though since those are essential to a cars ignition system (senses what position the pistons are at so it can tell the coils to fire when they need to). Some vehicles however (04 Kia Optima) rely on both to run the vehicle. They are fairly easy to test with a DVOM, I could send you diagrams tomorrow from work if you want to DIY.

If you could get the CEL checked and get back to me it'd be a lot easier to help though.

[Fr34k]

I have an 08 Envoy, while I'm sure some of these suggestions may help you find the problem I would suggest you post on a forum dedicated to this platform. Trailvoy is the older site, kind of dead now but you might find old posts or articles with similar problems and hopefully solutions. If not you can try GMTNation. Super active site, lots of great members who are super helpful.

Honestly if you were on that site before dropping 910 on plugs and wires, you could have probably found a writeup on how to do it and saved yourself easily hundreds of dollars. I'm assuming you have the 4.2L I6 engine, coils and plugs are a piece of cake on that motor even with no mechanical experience. Everything is right at the top of the engine, it could probably be done with a basic socket set (guessing 10mm for coils, and 5/8" for spark plug socket) in about an hour or two.

I'm sure someone there can help pin point your problem, I've had plenty of help from there over the last 4 years.

[Byrthnoth]

Yeah, never go back to those mechanics again. They blatantly charged you almost a grand to do super easy maintenance that they knew had nothing to do with the problem.

[Corrderio]

Did you ever get anyone to tell you what the Service Engine Soon light codes were? Autozone will check them for you for free. When you get up in the morning and go to start the car, does it start without problem or does it take a while? How long after you first start the vehicle and begin to drive it does it die? The fact that it's dying while driving eliminates a lot of what was suggested above.

Ace is pretty close, could be a faulty cam or crank sensor. More so crank sensor though since those are essential to a cars ignition system (senses what position the pistons are at so it can tell the coils to fire when they need to). Some vehicles however (04 Kia Optima) rely on both to run the vehicle. They are fairly easy to test with a DVOM, I could send you diagrams tomorrow from work if you want to DIY.

If you could get the CEL checked and get back to me it'd be a lot easier to help though.

For the codes, no they didn't. All they said was it was something with the power and cleaned the connectors to the battery. They said if it comes back again they might have to replace something, but I forgot the name. I'm going to try to contact them and hope they have me on record since the closest Autozone to me is over an hour away.

As for ignition, it starts up without a hitch. The times when the motor go were random. At the first light I'd say it took about 8-10 minutes til I hit the light where the motor went for the first time. About 5 minutes or so before I hit the light yesterday.

[Corrderio]

Well I tried a Mechanic about a mile from where I worked. He said it can't be the fuel pump if I don't have a problem starting the car. He also listened to the ignition for anything suspicious and said it sounds smooth. He also doubts they can find the problem since nothing is coming on my dashboard and no real leads to go on other than it stopped in two situations when I was at a red.

[Quixon]

I'm betting on the Cam/Crank Position Sensor personally.

Find a forum specific to your vehicle and copy/paste your OP. I guarantee you'll have an exact answer in less than a day or two.

Get the codes read as well. Autozone will read them for free, or you can buy a cheap code reader for like $15-20 from them.

Why the hell did you pay them $900 to do work they were not supposed to do? Mechanics can't just change shit without your consent and then Bill you, unless you tell them that's ok.

How many hours of labor..... Because parts were probably <$500 and it's an hour labor max.

[Corrderio]

They said the spark plugs were pretty beat to and near their due time. I had no clue labor for it would be damn near 500 bucks though...

I'll have to try and find a mechanic that will give it a go though. Graham said they wouldn't know where to look since I don't have much to go on other than the engine idling and my dashboard's service light not picking up anything.

[Acevalefor]

Go to just about any auto parts store (Baxter, Autozone, O'reilly, Carquest, etc.) and they will test the CEL for free. They will also test the battery and connections for free. Re the hill thing, you would notice a lack of power going UP a hill if it was fuel related. The vehicle would try to compensate for a lower fuel flow by lowering the air intake if the fuel pump was not working. It sounds like that is not the issue though, so disregard.

If you do not want to take it back to a mechanic, which I recommend, you can buy the magnetic sensors for the crank and/or cam shafts for fairly cheap. I think mine was $22 for the cam sensor; and replace them with a 5/16 socket and a small screwdriver to pry the electrical plug clip off. It is very easy as long as it is not inside the timing chain cover (Hello '99 F-150). It can't hurt anything to replace them and you are out <$100 instead of another $1000 for something that didn't need doing.

[Corrderio]

Oh derp, sorry. And no, I don't think I've notied anything. Then again, the streets are pretty level here so that might be a tough one.

I'll try giving looking up a place this weekend since most stores are closed by the time I leave the office.

[elison]

Go to just about any auto parts store (Baxter, Autozone, O'reilly, Carquest, etc.) and they will test the CEL for free. They will also test the battery and connections for free. Re the hill thing, you would notice a lack of power going UP a hill if it was fuel related. The vehicle would try to compensate for a lower fuel flow by lowering the air intake if the fuel pump was not working. It sounds like that is not the issue though, so disregard.

If you do not want to take it back to a mechanic, which I recommend, you can buy the magnetic sensors for the crank and/or cam shafts for fairly cheap. I think mine was $22 for the cam sensor; and replace them with a 5/16 socket and a small screwdriver to pry the electrical plug clip off. It is very easy as long as it is not inside the timing chain cover (Hello '99 F-150). It can't hurt anything to replace them and you are out <$100 instead of another $1000 for something that didn't need doing.

No point in changing things without knowing they need to be changed. To the tech that told you he can't diagnose it because there isn't a CEL, that's not true. Intermittent issues happen all the time. There are many things you can check, test and verify with or without a scan tool. Sounds like he's lazy and doesn't want your money. Oh well.

[elison]

Dumb phone

[elison]

No point in changing things without knowing they need to be changed. They are extremely easy to test and some of them are really expensive. Don't waste your money on just a hunch. To the tech that told you he can't diagnose it because there isn't a CEL, that's not true. Intermittent issues happen all the time. There are many things you can check, test and verify with or without a scan tool. Sounds like he's lazy and doesn't want your money. Oh well.

Oh and I realize you paid a shit load for some plugs and what not but it's not like he put a gun to your head and made you change them. I always love when people bitch about things like that AFTER they agreed to do it in the first place. Your job as a consumer is to do some research, call around for some prices and see if things even need to be changed. Rule of thumb is plugs usually last 100k,coil packs is random without a set life. Sometimes they just fail.

[elison]

Double