Silverado problem. Any ideas about what could be going on here? - Page 1

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[ARCHIVED THREAD] - Silverado problem. Any ideas about what could be going on here?

Posted: 10/30/2015 3:34:35 PM EDT

It's probably pretty simple, but I know next to nothing about vehicles. The truck is a 2003 Chevy Silverado with about 70k miles on it. I hadn't driven it in a few days prior to the onset of problems and there was no indication of any issues at that time.

On Monday evening, I started the truck up and it started running pretty rough and then cut off after about a minute. It did this several times, and then again about an hour or two later. A couple of hours after that, I started it up again and it seemed to be idling fine and did not cut off. This afternoon, it started up normally and seemed to be running okay, so I took it out an drove around a few blocks. It seemed to mostly run fine, with a couple of moments where it seemed to be lagging. When I got back to the house, I noticed some white smoke from the exhaust. When I got out, the smoke smelled like the smoke from a lawnmower and the truck cut off after a few second. I started it up again and the smoke just smelled like regular exhaust, but very strong smelling(and so strong that it actually got in my clothes after a few seconds). Everything looks normal under the hood and the fluid levels all appear to be normal as well.

Any guess at what could be causing this?

Posted: 10/30/2015 3:38:05 PM EDT

[#1]

Is any check lights on the dash? imo it can be a few things. really bad plugs, fuel filter, fuel pump, coils, and of course something internal. When was the last time a basic tune u was done to it? does it sit for long periods of time?

Posted: 10/30/2015 3:43:04 PM EDT

[#2]

Survey says fuel pump #1 answer. seems like every Chevy the wife has had needed a fuel pump about 70,000. We started trading them at 50000 to avoid it.

Posted: 10/30/2015 3:43:41 PM EDT

[#3]

fuel pump

Posted: 10/30/2015 3:44:52 PM EDT

[#4]

Quote History

Quoted:
Is any check lights on the dash? imo it can be a few things. really bad plugs, fuel filter, fuel pump, coils, and of course something internal. When was the last time a basic tune u was done to it? does it sit for long periods of time?

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Forgot to mention that the check engine light was flashing. It's probably been a while since it had much work done on it. I got it serviced a few months ago, but I don't recall much getting done besides the fluids getting changed. It's not uncommon for it to sit for a few days at a time, but that's about it. Never more than a week.

Posted: 10/30/2015 3:47:15 PM EDT

[#5]

If its possible, either have someone bring an OBD II scanner and scan your truck to see what codes are popping u. usually this tell u what ur problem is. if no 1 has 1, just go to any autozone, check, orieleys, and they will scan it for free and tell you what the code/problem is. since there is a check engine light on, i wouldnt really start "guessing" what it could be cause that will tell you what is wrong.

Posted: 10/30/2015 5:03:45 PM EDT

[#6]

Flashing CEL indicates a misfire. Is the CEL light staying on, or did if just flash and then go off? If the light is staying on, you have some codes to read.

Could be the fuel pump. Turn the ignition to run, but don't start the engine. Do you hear a whine from the fuel tank? The fuel pump on my '01 Suburban died around 115k miles. But it went quick - all of a sudden, the engine died and would not restart.

Maybe a problem with the mass airflow sensor or oxygen sensor is causing it to intermittently run rich? Just guessing here....

Posted: 10/30/2015 8:23:10 PM EDT

[#7]

I'd bet you've got an intake manifold gasket leaking. Every truck I've owned with an LS engine has done it at one time or another.
While you've got it apart, replace the knock sensors.

Posted: 10/30/2015 9:06:54 PM EDT

[#8]

Quote History

Quoted:

Forgot to mention that the check engine light was flashing. It's probably been a while since it had much work done on it. I got it serviced a few months ago, but I don't recall much getting done besides the fluids getting changed. It's not uncommon for it to sit for a few days at a time, but that's about it. Never more than a week.

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Quote History

Quoted:

Quoted:
Is any check lights on the dash? imo it can be a few things. really bad plugs, fuel filter, fuel pump, coils, and of course something internal. When was the last time a basic tune u was done to it? does it sit for long periods of time?

Forgot to mention that the check engine light was flashing. It's probably been a while since it had much work done on it. I got it serviced a few months ago, but I don't recall much getting done besides the fluids getting changed. It's not uncommon for it to sit for a few days at a time, but that's about it. Never more than a week.

Flashing CEL indicates a misfire. Nasty smelling exhaust and poor/idling also indicates a misfire.

Need to determine if it's random or one cylinder. Get a code scanner. P0300 is random, the rest are individual cylinders.

Individual cylinder misfire codes (P0301-8) would point to fuel injector or spark plug/coil wire.

Fuel pump issues are extremely common on these trucks. Mine is on its 3rd.

Plugged cats are also common on these trucks. When mine went, it started misfiring badly under full throttle.

GM crank sensors are notorious for failing. Generally will cause random misfires. Usually, a failing sensor will stall at random times and run fine at others. MAF sensors do that as well, and can cause misfiring if faulty.

Posted: 10/31/2015 11:46:43 AM EDT

[#9]

If it's loading up with fuel (the smell on your clothes) I doubt its the pump and more like a sensor that's not performing well.

Easy fix, get some Mass air flow cleaner from Autozone and spray your MAF. (spraying into the screen side) to clean it. You'd be surpised how a MAF that is barely barely dirty can cause havoc on the system. Especially in OPEN Loop when the engine is cold and not reading off the O2 sensors like when it's warm and in closed loop.

Posted: 11/27/2015 8:40:01 PM EDT

[#10]

I finally managed to get a little bit done on this. Still no resolution though. After I figured out that there was a blown fuse preventing the diagnostic port from working, I was finally able to get the codes pulled today. Random misfire. I pulled the MAF sensor off and cleaned it a few days ago, but nothing changed with it. It no longer cuts off, but the fuel rich white smoke is still there, usually just a little bit, but occasionally a shitload of it when I stop at a stop sign or a red light. I had to replace the battery today, so I'm going to give it a few days and get the codes pulled again to see if anything else comes up. I'll probably go ahead and change the spark plugs and maybe the plug wires too.

Posted: 11/28/2015 1:59:08 PM EDT

[#11]

Ive had some similar issues with my 07 Yukon XL. Showed a misfire so I pulled the spark plug wires and one of the wires stayed on the plug. New wires and new plugs and it now drives awesome. Even gained about 4mpg on the highway. 126k miles and Im not sure that the plugs were ever changed.

Posted: 11/28/2015 5:05:19 PM EDT

[#12]

Pull the vacuum hose off of your fuel pressure regulator......... If it has gas in it, it is shot and dumping fuel directly into the intake manifold. Takes 5 minutes to change it if it's bad.

Posted: 11/29/2015 1:32:18 PM EDT

[#13]

Quote History

Quoted:
Pull the vacuum hose off of your fuel pressure regulator......... If it has gas in it, it is shot and dumping fuel directly into the intake manifold. Takes 5 minutes to change it if it's bad.

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Where I would start.