IIRC you've already done the usual things to address a misfire: coils, plugs, injectors.

The mechanic has diagnosed the source of the misfire as a sticky lifter. I've never encountered a sticky lifter in any engine though admittedly the number of engines I've been in contact with at that level is under 50 and that's probably high.

But based on what I read on the various forums sticky lifters do not seem to be common.

The only Porsche cars -- 2 -- I've encountered with any valve trouble is years ago, shortly after I bought my 02 Boxster I found a very very low miles used 02 Carrera and I asked about the car and the explanation was it developed a noisy lifter which was fixed under warranty but the owner had soured on the car due to this kind of repair so early after buying the car.

More recently -- within the last year or so -- I came across a Boxster in for a broken valve spring. This car was owned by a woman who used the car as DD. The car had around 60K miles and I spotted the head off and looked at the head at its combustion chambers which were so free of any deposits I thought the head had been cleaned, but the tech told me that the head was as it came off the engine.

The only other car (within the last couple of decades anyhow) that had a valve problem was a co-worker's Subie which generated a misfire error code. Eventually he had this looked into and the cause was a burned valve.

So, what does this mean? Everything or nothing. We are back to your tech says it is X (sticky lifter). The fact the symptom is not present all the time doesn't necessarily render his diagnosis invalid. Have you talked to him about this intermittent characteristic and heard what he has to say?

I note you mentioned you washed the car and then drove it some time afterwards. That's good.

But it prompts me to ask: Do you sometimes wash the car and then do not drive it afterwards?

I know my Turbo's engine gets wet after a wash because when I start the engine I often hear the belt squeal from the water.

Anyhow, if you wash the car and then fail to start the engine and drive the car to thoroughly dry the engine (and the brakes too but that's another post), the misfire could be due to dampness arising from this treatment.

Even though the coils are new they are not 100% immune from a large dose of moisture. Also, the problem may not be the coils but a related and marginal electrical connector/connection which allows a bit of moisture in which can interfere with a coil's operation.

If the engine is cold or even warm, and then the car is washed, and not driven to dry the car/engine, the small amount of engine heat is not sufficient to dry the moisture but just make a nice humid micro-climate in the engine compartment.

Next engine start and for some time after... misfires are possible. In fact if the problem were a connector/connection this can take some exposure to heat to dry the moisture. Also, the presence of moisture can result in a corrosion problem that could have the misfire problem present even though there is no moisture present.

Sincerely,

Macster.

 

I drove mine for 2 years like this with intermitent rough idle and lastly CEL. I lived with the CEL's for a few months and then finally bit the bullet. With the broken intake cam I am glad I moved on it, so it's hard to know if you have something like this that could cause even more damage? Tough call but after my experience I would say to get it in to the shop.

 

A few points.........The lifters are on a dead end street as it relates to the oil supply .One of the reasons they fail is debris .If the oil going in is contaminated the contaminent is still there .It might move enough under pressure to allow the lifter to fill -but it has no place to go unless it dissolves .I don't think there is any way to say for sure it won't do it again .The hard part of this one is that for peace of mind -it would be better if the car was throwing cel's and the lifters were replaced and no more cel's .Especially when the lifters were targeted by the process of eliminating other things .
If it were me I would want the misfires up solid and the repair verifying that it was fixed .Which might happen if you drive it some more .

 

The lifters receive filtered oil. They are no more on/in a dead end than any other critical oil interface.

The lifter body has a chamber which receives the oil -- via a hole in the body fed by a groove around the bore in which the lifter resides and this groove intersects an oil supply hole fed by an oil galley in the head -- and this chamber acts to trap any particulate matter should there be any in this oil.

(In the 993 engines Porsche had a bypass filter intended to filter out the finer particles that made it through the standard oil filter but dropped this bypass filter because it proved to not be necessary. The primary filter filters sufficiently.)

The zero-lash portion of the lifter is in this chamber receives its oil not by a direct path but from simply being in the enclosed chamber into which oil under pressure is fed which in turn supplies the same oil pressure to the zero-lash adjuster.

There can be an internal oil leak, a camshaft cover's 'seal' (a bead of sealant that of course gets flattened out when the cover is installed/tightened down) develops a leak that allows oil to leak away from where it should be into the area under the cover.

This bead not only seals the oil inside the camshaft cover but keeps oil under pressure from being leaked out internally. If a leak has developed one (or more) lifter bores (in which the lifter bucket resides) may not be receiving a sufficient supply of oil. The result is a zero-lash adjuster may not pump up properly.

Eventually due to lack of sufficient oil the lifter assembly degrades -- and even the cam lobe can be affected for the cam lobe/lifter bucket top are lubed by oil that seeps out around the bucket and its mating bore in the head assembly -- and then can begin to stick or just as likely has developed large (too large) clearances and the zero-lash adjuster no longer functions properly.

(The fit of the zero-lash adjuster mating parts is so precise that even without any oil the fit so close that it acts as a seal and the zero lash adjuster is hard to squeeze/compress due to the air trapped in the small zero-lash chamber.)

Sincerely,

Macster.

 

Macster-nice write up .The point on dead end is that once oil/foriegn object is in the lifter it's there for the duration .This is not the case with the cam follower -if the hole on the cam follower is at 6:00 the oil will probaly seep out .Since this appears to be somewhat intermittent it is likely something is floating around .One would think that if it was a leak or insufficent supply the components would seize and not be intermittent .But you never know..........

 

Macster, dcdrechsel, and the others who chipped in - Thank you all so very much for your help. The good news is the problem is solved. It was a bad intake valve lifter indeed.

I got it replaced and been running for about 2.5 weeks now and it is running perfect. No misfires, no CEL. I did see the faulty lifter after the mechanic got it out. It was just one lifter on cylinder 6 that was just getting stuck if you tried to move it. It was way extremely hard to push it down while the others would move like silk. That culprit caused me 6 months of pain!!! Hopefully, I won't have to deal with this again. Fingers crossed!

 

Good, glad you got it resolved and fixed. Did you change just the one lifter or the entire bank? Someone here indicated it's always/nearly always #6. Is that true?

 

Yep, mine was cylinder 6 too. I wanted to change all the lifters from that bank but the mechanic tried but could not get to it without having to drop the engine and do it. So, I got 2 intake lifters and exhaust lifters on 6 replaced and am returning the rest back to Sunset. I am hoping the other ones will not be an issue. From what I have read too, #6 is always the problematic one. There is no logical reasoning as to why though.

 

Thanks for the feedback and glad it is a happy conclusion ...........

 

Not sure about the mechanic saying that he would have to drop the engine to replace the other lifters on the 4-6 side. To change any lifter on a side you have to take off the cam cover and remove the cams, and oncevthat is done you have easy access to all the lifters on that side. Seems strange that he said he could not do the others. Jake Raby has said that he often finds many of the lifters on an engine stuck. I know several of mine were stuck when I took the out.

Good to hear that the car is running well, now enjoy it!

 

Yeah plus 1 on that, once the cams are out test every lifter weather you think there is a problem or not!

 

Old thread but I found it while hunting for a Lifter problem.As the OP explains -it can be a $4000++ job!
I posted some extra info here:
https://rennlist.com/forums/boxster-...grade-fix.html

It seems there are two issues:
1.the lifter part number(& design?) has been upgraded to address the sticking problem(?)
2.Generic or even re-branded OEM ,INA lifters are available more much less than quoted by the OP.
That suggests a replace-them-all strategy because of the labor involved and the potential for expensive collateral damage.
Let the Forum know what you do to help others in this situation?

 

Old thread but I found it while hunting for a Lifter problem.As the OP explains -it can be a $4000++ job!
I posted some extra info here:
https://rennlist.com/forums/boxster-...grade-fix.html

It seems there are two issues:
1.the lifter part number(& design?) has been upgraded to address the sticking problem(?)
2.Generic or even re-branded OEM ,INA lifters are available more much less than quoted by the OP.
That suggests a replace-them-all strategy because of the labor involved and the potential for expensive collateral damage.
Let the Forum know what you do to help others in this situation?

 

Can someone confirm if the lifters on bank 1 (cylinder 3 specifically) can be replaced with the engine in the car? I've looked but can't seem to find a DIY for that.

 

Why are you replacing the lifters for cylinder 3?