Loss of power/ smoke

Car cuts in and out at around 2500-3000 rpm. Doesn't always do it and sometimes stays a limp mode. Recently replaced MAF n75 and MAP sensors and timing belt was done by VW. New to TDIs so I'm still learning all this and not really sure what I should do from here. Any help would be appreciated.

You didn't say how many miles are on your vehicle, but mine had a similar issue at 123,000 miles. I did not have a limp mode issue, but I did have some black smoke and loss of power whenever the engine was under load (accelerating). At steady speed I had no noticeable issues. I had a bad cam lobe (one went soft and wore down, thus a valve was not opening properly). I had replaced my MAF with an aftermarket German MAF to try to fix the problem, but it turns out the generation or version of MAF that I installed was older than what the car required, and that also caused a code (I don't know which one). The dealer sorted everything out for me, as I would not attempt a cam replacement by myself, even if I could diagnose it. New cam = runs like a champ again.

Sorry car has 123000 miles. The problem is intermittent and doesn't happen all the time so seems more of an electrical issue but correct me if I'm wrong. I replaced the MAF with a Bosch one is that what it should be?

Also glow plugs were changed because one went bad old were NGks and were replaced with the oem steel plugs

I assume you had the EMISSIONS WORKSHOP appear on the dash, did you read the codes yet? Based on your description it could be a few things including 1) As fastcar said, likely a cam lobe issue and 2) a blown/cracked intercooler hose

Yes I had the emissions workshop and the dealer said it had codes for the n75 and MAF sensor. Don't have the vcds to read the codes myself.

Any OBDII scanner can read the codes (free scans at Autozone or the dealership...). It's 'probably' not your MAF sensor. The MAF failure is basically confirming you that you have too much fuel for the volume of air getting into your cylinders. Again, possibly CAM shaft related or your Intercooler hoses. Those seem to be pretty common failures for us B5.5s.

Ok I'll check all my hoses for visible cracks any good way to test? Also any links or information on checking/ replacing lobes?

Also have no check engine light on and not getting emissions workshop since n75 map and glow plugs were changed

The ngk plugs are the correct gps for your car. The voltage is not the same as the older bosch plugs which you had installed and will burn out quickly. Not only are the ngks much less expensive, but they perform much better in cold weather.

When my cam went bad, the problem was a very slight power loss since the cam lobe wore slightly. From occasional stutter to loss of power when sinking into the accelerator was 2 weeks and a couple of hundred miles. The hardness of every lobe on a cam can vary. I eventually got the emissions workshop light. To replace a "lobe" you have to replace the entire camshaft and associated parts. idparts sells the cam kit at a reasonable price for the B5.5 TDI BHW engine if you can find an independent shop to do the work. I had West Houston VW do mine and parts and labor was about $3,500. They had the car for a week due to parts ordering and some other things I had done to the car, so I got a loaner car for the week. An experienced technician needs to look at the cam. Still yet, your problem could be something else. My dealer happens to be up to speed on what goes wrong with these BHW engines, so my experiences have been painless if you discount the $$$.

fastcar4re said:

I had West Houston VW do mine and parts and labor was about $3,500.

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Wow! I had mine replaced parts and labour all in for under $1000.... Probably about $800.

I can't seem to find ngk plugs for the bhw. Any good shops you guys would recommend in DE PA MD or NJ. The dealership here doesn't seem to know too much about TDIs.

Your friendly local VW dealer has the ngk plugs. Give them the vin # of your car and they'll give you the correct plugs. Be sure to replace all 4, not just 1 or 2. They are about 44 bucks for all four.

Just got back in town and tried unplugging MAF and driving. With MAF unplugged car does not have a rough idle but doesn't accel as it should. Put dielectric compound on plug and tried to accel quickly car sputtered around 3krpm and emissions workshop and check engine light came on. Going to check the code tomorrow. Any ideas?