Venture Engine light on intermittently

[akbarker]

My 2000 Chev Venture has been acting up a bit lately. It started a slight bucking at 105000kms and seemed to be shifting a bit hard also. I have since changed the transmission oil and filter and fuel filter. Over the last week I have noticed a lack of power when it shifts into overdrive and this a.m. it had no power when I attempted to accelerate from approx 80 km. The engine light blinked a few times then went away. I do not have a code reader and live in Canada, so likely would have to pay for a scan, but before I do are there any ideas out there??

[cdru]

A blinking CEL is notifying you of a severe misfire on one or more cylinders. That, coupled with the lack of power make me wonder about a plugged cat converter. The plugged converter allows for too much back pressure which can really confuse the computer (let alone screw things up).

It could also be as simple (as if anything with these vans is simple) as just needing a tuneup.

[akbarker]

Originally Posted by cdru

A blinking CEL is notifying you of a severe misfire on one or more cylinders. That, coupled with the lack of power make me wonder about a plugged cat converter. The plugged converter allows for too much back pressure which can really confuse the computer (let alone screw things up).

It could also be as simple (as if anything with these vans is simple) as just needing a tuneup.

Just talked to a GM service guy in Saskatoon, hey suggests that the usuall problem with 3.4l misfiring starts with the injectors, they can clean them (including the EGR) for $139.00, if that doesn't work then the plugs, wires etc. Would it be worth throwing a can of concentrated cleaner thru or just bite the bullet. Also removed one plug to check for deposits, what a pain to get those wires off (think I screwed it up) so will likely have to replace the wires now also. Tips??

[cdru]

The injector cleaner you put in your tank likely would do nothing. I'd find out exactly what they are doing to clean them. Are they removing them, or cleaning them in place by "backwashing" the fuel rail with injector cleaner.

[akbarker]

I think it is safe to say that for $139.00 they are not likely to remove the intake to get at these things, (unless it looks easier then it appeared to me, it is not hard but you don't get much for $139.00). Which would suggest a clean in place method. After reading a few other strings yesterday I decided to check the oil fill cap for a white scum, and wasn't surprised to see that there was a small coating on it. Is it true that this likely means a head gasket is shot? I have not notice any significant coolant loss. If so it would likely be in my best interest to pull the injectors when I get around to the head gasket and take them in to a shop for cleaning. Has anyone else out there in Canada had any luck with GM picking up some of the costs on the ever popular head gasket issue??

[cdru]

Originally Posted by akbarker

I think it is safe to say that for $139.00 they are not likely to remove the intake to get at these things, (unless it looks easier then it appeared to me, it is not hard but you don't get much for $139.00).

That is likey correct. It took me around 45 minutes to remove my upper intake the other day. So figure 2x that for the complete process and you are already at $140 just for shop labor and you haven't even touched the injectors.

After reading a few other strings yesterday I decided to check the oil fill cap for a white scum, and wasn't surprised to see that there was a small coating on it. Is it true that this likely means a head gasket is shot?

Not necessarily. Cold weather is here. What were the driving habits of the vehicle? If the van never gets hot, the moisture just from the air will never get vaporized. So you may get some accumulation. My van is like that. My wife only drives about 5 miles to drop off my sons at a nursery school usually, so it never gets hot enough to burn off the water. If you want a definite answer, you'll have to send an oil sample in to be examined for antifreeze. It only costs $20.

I have not notice any significant coolant loss. If so it would likely be in my best interest to pull the injectors when I get around to the head gasket and take them in to a shop for cleaning.

If you do an intake or head gasket job, you will be removing the injectors anyways. Normally you would just leave them connected and bend the fuel rails out of the way (the lines are flexable). They are quick connect fittings so it would be fairly easy to just take in the whole rails.

But I wouldn't jump to conclusions that you have a head gasket problem.

Has anyone else out there in Canada had any luck with GM picking up some of the costs on the ever popular head gasket issue??

Intake gasket, maybe. Head gasket, very doubtful. It's not nearly as much of a problem as the intake gasket. Remember that just because you see a lot of posts here about it doesn't necessarily make it an epidemic.

[akbarker]

Thanks a bunch, you have answered a lot of questions. The van travels short distances and has no external leaks so I see what you are saying about the moisture, I will have the oil analyzed at the next oil change. Is there any way to check the intake gasket for leaks?? could this lead to the misfire problem that originated this string of questions.

[cdru]

A bad intake gasket I don't think would cause a misfire. With the way the intake is designed, there isn't any air passages that run next to a coolant passage. All the different passages have independent seals around them in addition to gaps in material.

The only exception to this is that the gasket could have failed around an air passage and allowed unmetered air to enter the cylinder. This could cause a misfire/stumble, but again I don't think this would be likely.