3.0L Misfire

[pmelv8sho]

I have a '02 Vue 3.0L with 99k. I have been doing all the expected service work at this mileage. The timing belt kit from rock auto and water pump were done about four of five months ago with 94k.

About a month ago I had a check engine light come on. It showed a misfire, but the engine was running ok. I decided to have the spark plugs changed at a Honda dealership (no Saturn or former Saturn store where I live). When this was done they also said there was a slight vacuum leak from the gasket on the flange. They said to drive it until it gets worse.

I drove the Vue for a couple of weeks until it started to run rough just a few minutes after starting it. I scheduled it for the gasket work. I also ordered both coil packs and a thermostat from rock auto. I had the Honda dealer (former Caddy, Pontiac & Buick dealer also) do the work.

Here is my problem. They are having misfire codes P0301, P0303 and P0305 appear and the Vue still runs rough a minute or two after starting. They have had the thing apart four or five times looking for something that was done wrong and can't find anything.

They have tested the cats and they are within spec.

Help, thoughts or ideas?!?

[yzracer14]

It could possibly be the intake manifold gaskets. There is a plate between the engine block and the intake manifold itself. What is the gaskets on the flange you're talking about?

[pmelv8sho]

They told me there was a molded gasket on some flange that is basically the intake gasket?!? Did I misunderstand them?

[Someclown]

Originally Posted by pmelv8sho

Here is my problem. They are having misfire codes P0301, P0303 and P0305 appear and the Vue still runs rough a minute or two after starting. They have had the thing apart four or five times looking for something that was done wrong and can't find anything.
They have tested the cats and they are within spec.
Help, thoughts or ideas?!?

If the MIL is flashing, do not drive the vehicle or it WILL destroy your cats.
Have you changed the coil packs yet? If so try the old coil pack on the side with pistons 1,3,5 as these codes are telling you cylinder 1,3,5 are misfiring
I was going to guess the cam or crankshaft sensors got damaged or didn't get plug in when other work was performed but if this was the case all six codes should show up PO301-306
BTW,The lower intake flange and intake manifold both have molded gaskets which should be changed whenever these items are removed or air leaks may arrise

[pmelv8sho]

The coil packs have been change and they did try the old one on that bank and the same problem continued.

I have driven the vehicle maybe fifty miles since this started. It has been in the shop for two days now.

I had a new flange with the molded gaskets installed (Saturn part) on Monday. The have checked the intake gasket for leaks and have not found any vacuum leaks anywhere. This is a good shop but they seem about at their end of ideas...thus, I am here asking for suggestions

[nil5]

If the MIL is flashing, do not drive the vehicle or it WILL destroy your cats.

Not trying to be disagreeable, but I think this is an exaggeration, personally...

When the plugs were changed, a knowledgeable mechanic would have also replaced the thermostat and intake manifold gaskets should have been replaced, simply because of the amount of time it takes to remove the intake manifold in order to reach the plugs/thermostat.

Coil pack was a good guess, since it is a single bank (cyl 1,3,5). Another component that follows the cylinder bank is the intake runner flapper valves. Each bank has a solenoid which opens/closes these air passageways to make the intake runner shorter/longer depending on computer control (some function of engine rpm, load, i suspect, but don't really know).

Anyway, if one of those solenoids was not operating properly, maybe the flappers are stuck open/closed/in between somewhere and that is messing with the fueling when it is closed. Since the engine is cold/warming up, I would suspect that the flappers would be stuck in the state where the make the intake runner short, since this is the tuning that is good for high rpm operation.

That is just one hypothesis.

Other common things for that cylinder bank... maybe the fuel rail? Is there a section that splits to supply fuel to the rear injectors? Maybe there is something clogging the fuel rail there? Seems sort of unlikely...

Speaking from experience, I replaced the intake manifold gaskets. The OEM (i.e. factory) gasket is molded to the lower intake manifold spacer (you were calling it the 'flange'), but that doesn't mean you have to replace the whole spacer assembly (as you did, which i bet cost you a bit). You can buy the Felpro replacement from Autozone or your local autoparts store for $40 or so. It works fine, despite being slightly different than the molded piece. So, I think you got ripped off on having to by the new spacer, but that is moot, I suppose.

The Honda shop CLEARLY is not experienced with your VUE's 3.0L engine. There are people on this forum who are far more knowledgeable. I would recommend you find a good independent mechanic who has worked on more GM cars than the Honda dealer has, because they would have encountered the L81 V6 your VUE has if not in a Vue, then in a L-series, or Saab, where it was also used, and they would steer you straight. The Honda dealer also does not have the GM-specific electronic diagnostics equipment to potentially diagnose this problem without throwing so much more money at it.

I think your main problem is your mechanic. Find a new one ASAP.

[pmelv8sho]

Originally Posted by nil5

Not trying to be disagreeable, but I think this is an exaggeration, personally...

When the plugs were changed, a knowledgeable mechanic would have also replaced the thermostat and intake manifold gaskets should have been replaced, simply because of the amount of time it takes to remove the intake manifold in order to reach the plugs/thermostat.

Coil pack was a good guess, since it is a single bank (cyl 1,3,5). Another component that follows the cylinder bank is the intake runner flapper valves. Each bank has a solenoid which opens/closes these air passageways to make the intake runner shorter/longer depending on computer control (some function of engine rpm, load, i suspect, but don't really know).

Anyway, if one of those solenoids was not operating properly, maybe the flappers are stuck open/closed/in between somewhere and that is messing with the fueling when it is closed. Since the engine is cold/warming up, I would suspect that the flappers would be stuck in the state where the make the intake runner short, since this is the tuning that is good for high rpm operation.

That is just one hypothesis.

Other common things for that cylinder bank... maybe the fuel rail? Is there a section that splits to supply fuel to the rear injectors? Maybe there is something clogging the fuel rail there? Seems sort of unlikely...

Speaking from experience, I replaced the intake manifold gaskets. The OEM (i.e. factory) gasket is molded to the lower intake manifold spacer (you were calling it the 'flange'), but that doesn't mean you have to replace the whole spacer assembly (as you did, which i bet cost you a bit). You can buy the Felpro replacement from Autozone or your local autoparts store for $40 or so. It works fine, despite being slightly different than the molded piece. So, I think you got ripped off on having to by the new spacer, but that is moot, I suppose.

The Honda shop CLEARLY is not experienced with your VUE's 3.0L engine. There are people on this forum who are far more knowledgeable. I would recommend you find a good independent mechanic who has worked on more GM cars than the Honda dealer has, because they would have encountered the L81 V6 your VUE has if not in a Vue, then in a L-series, or Saab, where it was also used, and they would steer you straight. The Honda dealer also does not have the GM-specific electronic diagnostics equipment to potentially diagnose this problem without throwing so much more money at it.

I think your main problem is your mechanic. Find a new one ASAP.

The flappers were checked per my request earlier this morning. I was told they are working properly.

I was told the lower intake manifold spacer only came as a replacement in one piece. Just had to go with what I was told as I have never delt with this part of the engine before.

This Honda store is a former GM store (Caddy, Buick and Pontiac). We just do not have many Saturns around here. I am going to look elsewhere tomorrow if they can't come up with anything further.

Any other ideas as to what it could be? Thanks for the help thus far!

[bluesl2]

Hopefully one of the cams isn't out of time on that bank, I would be checking timing next.

[pmelv8sho]

Originally Posted by bluesl2

Hopefully one of the cams isn't out of time on that bank, I would be checking timing next.

This miss is bouncing around, with no rhyme or season, between the rear bank of cyclinders is what they are telling me. A timing issue would be very consistant.

[pmelv8sho]

I took the VUE to a Tire Plus store that has a few very good mechanics. They did flash the computer but the VUE still ran rough. They wanted to check the timing and I gave the go ahead.

It turns out the belt had jumped two teeth. They put it back together and it now purrs like a kitten. Problem solved!

Thanks to everybody on the board that helps with their suggestions.

[bluesl2]

That's why I mentioned the timing, you pretty much had checked everything else,good that it's fixed.

[nil5]

now, you should be asking yourself 'why did the belt jump two teeth?' Bad tensioner or improperly tensioned? I would be upset if I were you, as it sounds like someone didn't do the original timing belt job correctly.

[VTchemist]

I concur with NI5 about the Honda shop's knowledge of your engine. Your 3.0L is a L81, designed by GM Opel. It was used in VUEs and L-Series. It was also used in the Saab 9000 on the Caddy Cateras.

The L81 is a strange beast. A newbie mechanic, or someone not knowledgeable with it, could have problems.

If the tech that worked on it was a former Caddy tech, he should have not had problems. But the Cateras was only in production from 1997 to 2001.

If you have no success with the Honda shop, look for an independent shop that is very familiar with European engines (Bosch parts...). You may have better luck there.

Hope this helps...

[pmelv8sho]

Originally Posted by nil5

now, you should be asking yourself 'why did the belt jump two teeth?' Bad tensioner or improperly tensioned? I would be upset if I were you, as it sounds like someone didn't do the original timing belt job correctly.

I actually did asked about the tensioner and was told it is good. I did ask how this could have happened. They said they were not sure. I am also guessing that the original job was not done 100% correct.

At this point I am just happy that the VUE runs like new again