pulsing idle now no power

For several weeks my 2000 jetta with 210k miles on it has been pulsing or surging at idle. It doesn't happen all the time but when it does it is very rythmic going from about 700rpm up to 1000 rpm. The glow plug light started flashing maybe a week and a half ago and some info here said to check my brake lights for a bad bulb, which I found one blown out. I thought I read that the glow plug ligth blinking could also be could be code for the injector pump having issues, but now i can't find that reference. I figured that since I had a brake light out that that may be the cause of the light flashing.

I changed the fuel filter saturday and the surging didn't come back until today on the way home from work at a stop light. A few miles later I heard a distinct pop from the engine compartment and lost most engine power. It still idled just fine but I quickly pulled into a gas station and popped the hood. After looking things over with the engine idling perfectly I thought maybe i had hit something in the road that caused the noise so I pulled out of the parking lot. While idling out of the parking lot i did not notice any issues. Reving the motor seemed fine. As soon as I gave it a little gas while in gear it ws obvious there was no power. It also seemed to buck and surge until I pulled into the next lot. I cannot hear the turbo, but i have always struggled to hear it on this jetta. It does not feel like the "no power" when the MAF goes out. This was get out and push it lack of power.

So I will pursue getting someone to check it out with a VAG, but any ideas of what could cause this? Blown turbo? Blown Injector pump? I had the timing belt take out the head two years ago and KarmaTDI fixed it up for me with a new head and all new timing belt stuff. I could not hear any out of the ordinary noise in the engine compartment while idling or reving it. Give me your thoughts.

Does the power come back momentarily after you turn off and restart the engine?

Get a scan with VAG-COM/VCDS and see what codes there are, if any.

Sounds like you have more than one issue. The flashing GP light is the indicator of a bad bake light switch. Your switch needs to be replaced, even if the bulbs might still be working.
Upon restarting does the car run ok before acting up again? At those miles you may need injector nozzles, if they're causing your idle condition it could be very bad. If those are ok, have you performed normal maintenance on the air filter and snow screen? You may want to try unplugging the MAF to see if it runs better.

Thanks guys. I still haven't had it Vag'd yet but I pulled it in the garage today and found the intercooler hose disconected near the windshield washer bottle. What would make this pop off? This would allow unmetered air into the system and cause it to run like crap right?

The intake was about half clogged and the EGR valve was pretty gunked up. Another interesting find was the hard plastic hose that goes over the belts and down to the IC. I had some body work done because of an accident last year and it looks like something shifted that hard hose towards the accessory belt. The pulley was randomly rubbing the hard hose. There were four 1/16" holes in the hard hose. Would this have been enough unregulated air to cause the pulsing issue?

Everything is put back together now. I think the holes in the Hard line going to the IC actually came from when that hose blew off the IC and shifted into the pulley on the motor. I have power again, but still have the rpm pulse at Idle every 2 seconds. I get someone to Vag it nect week. It seems to run alright, but it just doesn't seem as smooth as it did a long time ago. Will the Vag hookup tell me if specific injectors are misfeeding or if something else could be causing the slight roughness to the engine?

The Group 13 values might show misfiring injector.

If it's every 2 seconds that could be EGR related?