Shaking Engine -Rough Idle -Rough Start

Went to start the car the other day and it was violently shaking when I cranked the engine and did not start instantly as it normally does. I had to double check to make sure it was in park because it was shaking so much. As if it was a manual and I was trying to start it in gear.

Once it started it was idling rough and shaking quite a bit. I had to keep revving it to keep it from stalling. It eventually smoothed out after about 10-15 seconds.

It was not very cold as the car was parked in the garage. It was around 0 C (32 F) I started the car with no issues in much colder temps couple weeks ago -22 C (-9 F).

So after it started it then seemed to go into regen mode right after.

I drove around the rest of the day and restarted multiple times with no issues. Next morning it started fine as well.


My two guesses are some sort of fuel deprevation occured or it has something to do with a failing DMF.

Fuel was at last quarter.

Has anybody else experienced anything like this?

Sounds like fuel deprivation to me. I'd dose the tank with powerservice white bottle and try to keep it more full. I've been keeping a 5 gal. can of K1 on hand this winter just in case.

fuel issue no doubt, Highly suspect a bit of water freezing in the filter. Like you said, starting is in colder temps was never an issue.

Here is some helpful information of getting rid of the water in the system.

Fuel conditioners or additives must also control water so it doesn't freeze to block fuel flow. There are two types of additives to control water: emulsifiers and de-emulsifiers. Emulsifiers break the water into microscopic droplets and prevent the droplets from joining together. The water is suspended in, and carried along with, the fuel. The volume of droplets is not great enough to block lines or damage injectors. FPPF is a typical emulsifier.

De-emulsifiers work the opposite way. They modify the diesel so it cannot hold water. The water, being heavier than the fuel, drops out and settles at the bottom of the tank. It cannot travel through the system to do damage, unless its level builds to where it is up to the level of the fuel pick-up tube. When using a de-emulsifier, such as Howes, it's a good idea to check the water level in your tanks with water-detecting paste on a stick. If there's an inch or less, no problem, but more than that, you should siphon the water out or drain it.

IMO You do NOT want to use the emulsifying type in a high pressure injector system. If the water gets to the injectors, it will flash into high pressure steam and tear the injector tips to pieces in very short order.

Get whatever chemical you want or prefer that will de-emulsify the water in your system, fun a half tank of it and run it down to Empty as you dare. Fill it up and change the fuel filter. Done

If your filter has a water drain on it, some do, you may not need to change the filter but just drain it empty out that drain and your good to go.

Cant think of any other reason your issue would be, 32 is way too warm for fuel to gel up.

The one i prefer to use is STANADYNE DIESEL PERFORMANCE FORMULA
https://www.amazon.com/STANADYNE-DIESEL-PERFORMANCE-FORMULA-OZ/dp/B004HQ9W3E/ref=pd_lpo_vtph_263_lp_t_2?_encoding=UTF8&psc=1&refRID=C8FRC1NJGP785PPCXCBS

But they are all kinda the same so your pick.

PS ive done this a few times on various tractors, trucks and my TDI and never had any issues and recommend it. When i added this to solve our ford tractors fuel issue, i had already drained the filter empty of a tiny bit of water and all the fuel in it. fan a tank though it with this stuff and ended up getting over 3/4 cup of water out of the filter separator when i had only originally drained less than a few table spoons out. Stuff works great.

phantom1260 said:

.... snip.....

Fuel was at last quarter.

Has anybody else experienced anything like this?

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Personally I drive only a small amount of miles.

Particularly I like to keep mine at half full in the colder months.

But I try to do an empty tank when I know I am going on a longer drive out of town -- then fill it as I get finished.

I'd wonder about intercooler icing. Take the lower pipe off the intercooler entrance and see if you've got fluid built up.

IndigoBlueWagon said:

I'd wonder about intercooler icing. Take the lower pipe off the intercooler entrance and see if you've got fluid built up.

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This makes more sense, OP drive a very short amount each day, not enough to get things heated up enough to get the condensation out of the IC

Next time OP, before you park it, give it a few good pulls at boost to make sure you get some heat going. Also putting some foam pipe insulation on your front grille can help keep the heat in.

This is why i always run a catch can or CCV delete and inject into exhaust to keep that moisture out of the system and for other reasons too.

frozen IC is more probable than water int he fuel issue i mentioned.

If it happens again, take the boot of the intake manifold and crank it back up, easy check.

My commute is about 40 km (24 miles) takes over an hour in traffic each way. So the car gets up to operating temperature. The night before there was a snow storm when it was parked. There was snow stuck all over the wheels etc.

So there might have been snow packed around the IC as well. The garage wasn't warm enough for the snow to melt.

So this could be possible as well.

I would also guess some water/ice in the inter cooler. I had this several years ago on my ‘12. When the conditions are right, water condenses/ freezes inside. Then the outside temp warms up a bit, to near 0, the engine heat when you park help to “warm up” everything in the engine bay and the ice melts. Next start whatever is collected in the bottom of the inter cooler hose gets sucked into the intake if it’s not refrozen! Some have had the engine hydro lock. Lots of good threads on this issue. Mine started rough, ran like crap for about a minute, smoked/steamed quite a bit then magically was fine. I had VW do the intercooler mod that is supposed to help with this issue shortly after. Then not long after all that I deleted the DPF/EGR and have never had an issue again.