Hmm, Ghost Codes?

[junior3382]

Okay, On my '98 Blazer, I had a engine light flash. I brought it to the shop and they found that it read a multi-cylinder missfire. But the weird part was, that after every possible diagnostic test, there was nothing found wrong with the truck. i saw the readings myself, they were well within perameters. The motor is running at near perfect performance. Since they cleared the code, it has never come back. It did this right when I first bought over a year ago, same story, there was nothing wrong. Is this a sign of a future problem? Or was this really just a Ghost code?


OOOO By the way, I am talking about the 4.3l vortec..... Sorry.

[mudseeker]

did the shop pull the freeze frame data? that would give you a good indication of what the engine was doing when the code was stored.

[junior3382]

Yes they did, and it did not indicate anything wrong.... Like I said, it did this when I first bought too, and there was nothing wrong with it. both times I passed 70mph on the freeway. But there was no hicups or spits in the motor. the O2 read normal and the TPS and MAP sensors all read normal. What concerns me, is that it threw the code with nothing wrong. Could the ECU be dying? I just do not want to be caught off guard with a bigger problem down the road. Especially with what I plan to do with the truck.

[436'd skylark]

did the mechanic spray water on the wires?

[junior3382]

Originally Posted by 436'd skylark

did the mechanic spray water on the wires?

What does that mean?

[436'd skylark]

if it threw a random misfire code, chances are the ignition system needs to be serviced. best way to check is to soak the cap and wires with water when its running. a good system will not even hicup.

[junior3382]

He did not do that, But I have. When I took it Muddin last time, i sprayed down the motor when I washed it. Of Course I left it running, and it did not skip a beat. So I do not think it is that bad off. The plugs and wires have less then ten thousand miles on them. The Mechanic said it was a fluke, and that these Chevy motors are known for that kinda thing. But I still hold that it had to have a reason for tripping. I just do not know where else to look. And it has not done it since...... Should I let it go, and see if it happens again?

[junior3382]

Okay, It happened again. Here is what is going on,

I had to run paperwork up to a customer. Had to go up through the mountains. I had the cruise set to 75 and in the passing lane. When I started to climb and incline, the truck was like a little kid on sugar, it down shifted and took off to maintain the speed. Runnin close to 3500 rpm's in what felt like 3rd gear the check engine light came on again. I immediately killed the cruise, and coasted off the freeway. I found an AutoZone and had it read..... Multi-cylinder missfire.... Again, not running different. They cleared the code and again no issues. Not running weird, and I hit 75 several more times after that, and no light. Should I be looking to replace something? Distributer, O2 sensor? Something that could tell the computer that there is something wrong, but not have a real big issue. I feel like I am being set up for a massive failure of sorts, and I am worried, but no one seems to have any answers. Any advice again would be helpful. There has to be a way to fix whatever this is.

[mudseeker]

i would take it to a shop or have a buddy at the dealership scan the truck and look at the datastream.

here is a good example for you. i was working on a 2000 f-150 with a no start issue. i had a dead power wire at the ignition switch. anyways i scaned the truck to check for more problems and it showed no codes, but once i ran the datastream i found the EGR was out of range and replaced it. the code did not pop up when at idle, but raise the revs to 2500 and the scan tool said the EGR had a problem.
may want to invest in a code reader from walmart for 100 bucks like i did. when a code sets it usually stores engine data at that moment. that info can be very helpful.
i'll post again once i'm done with work.

[junior3382]

Well I know exactly what you are talking about mud. I actually had that done last time. I held the laptop in my lap while the mechanic drove it. Ran through all gears, high reves, hard stops, even burned the tires and accelerated, then stoped and drove like a granny. The computer read everything is running fine. There were no hicups, no problems, no issues. But this code keeps appearing. It has them stumped as well as has me stumped. I personally hate computers because I do not trust them, but when everything on the truck runs on that computer, and IT says nothing is wrong, I have nothing to go on.

I got some advice on a different forum from a guy who said he had a similar problem and suggested just replacing the distributor now. He said that about six months after his truck had this code, the dist. quit. I would think if it is skipping, misfirein, or missing at all, that there would be a reading.

Even pulling the activity from the moement the code flashed, where it kinda takes a snap shot of the current stats, said nothing. Basically, there is no reason this code should be here.

My theory was that the ECU was beggining to fail. Perhaps it is flashing ghost codes because it itself is failing. And in which case, it would not admit that. I know a little bit of personification there, but I still hold that the truck is hiding something from me on purpose because it knows I can afford to fix it now, and will wait until I am broke, and NEED it to die. I know it is kinda morbid, and demented, but that is what I think......LOL.

I am very anxious to get the final answer to this one. Everytime I have ever had a problem no one could figure out, I always got a kick out of it. I would hear the words.... "WOW, I have never seen that before!" and I am anxious to hear those words again. LOL.