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Car does some "bucking" - PCV, EGR, IACV, Seafoam?
Hey Guys,
I'm trying to diagnose a problem that I've noticed for a while: my 03 TL-S (135k miles) will "buck" at certain, seemingly random times. It's acting as if the engine might not be getting enough of something, either fuel or air? It mostly happens after a bit of acceleration; I can feel the car want to start to buck so I'll lift off the accelerator pedal. It also seems to be more frequent on warmer, humid days and when on hilly roads.
No lights come on though; no CEL or anything.
I recently changed the spark plugs (NGK Iridium IX) and put a can of Seafoam in about half a tank of gas, so I think things should be OK on the fuel end. I'm thinking it might not be getting enough air?
If it is air related, based on what I've read on this forum, it seems like I should do some or all of the following:
- Replace PCV valve
- Check the IACV valve
- Clean EGR port
- Run Seafoam through the vac line
What do you guys think? The PCV valve thing seems simplest and cheapest... and within my skill set .
The Seafoam in the vac line should be optional right? Since I already put Seafoam in the gas? Or are those two unrelated? There were some posts mentioning another method of spraying Seafoam Deep Creep in through the air intake or something. Is that easier to try?
We've discussed what sounds to be the same issue here last year and all the people who chimed in, including myself all own TL-S models, but no solution to the problem was reported. Here is the link:
We've discussed what sounds to be the same issue here last year and all the people who chimed in, including myself all own TL-S models, but no solution to the problem was reported. Here is the link:
Ah, thanks for posting that thread. The issues do sound very similar. I guess it's good to know that it's not just me. Unfortunate that we don't have a solution though :/.
Many years ago, I had a similar vibrating/bucking issue, especially when the car was over 60 MPH and in low RPM, so 5th gear. I took it to the dealer and they did some cleaning of intake areas or something (can't really remember what they said) and it seemed to go away. The guy also said the intake gasket was on upside down, but, who knows how truthful they were.
Anyways, that's why now I think it's an air issue, but based on the thread, it sounds like its possibly a number of other things.
We've discussed what sounds to be the same issue here last year and all the people who chimed in, including myself all own TL-S models, but no solution to the problem was reported. Here is the link:
So, a few weeks ago, I went ahead and changed out the PCV valve. After driving for a few weeks, the problem has definitely mitigated.
Previously, after pressing the accelerator for a bit, the bucking will occur. However, now it usually won't buck and will continue to drive fine. There are a few moments now and then when it does happen still but rarer.
I think it has something to do with maybe pressure build up from pressing the gas. Anyways, it's a lot better, so if you haven't changed your PCV valve, could try it.
One thing though, when I went to change it, the diagram shows 2 parts: the valve (#2 in the picture) and a grommet (#4).
But on my car, there was only the valve. So that's all I replaced... I wonder if the grommet is useful? Granted, mine looks a bit different, but the repair manual does mention it...
08-30-2016, 12:20 PM
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