snowchaser

full acceleration. Going up I-80 Parleys the car will often jump, or miss under fulll throttle in the turbo zone. Tach stays up, and car actually seems to keep speed but the car will jerk some. Not easily duplicated in city driving but if I accelerate full power over 4K on the tach it will sometimes do it. Could this be simple spark plugs? It has been 50K. I have replaced fuel filter and pump and did not help

CarIsScrewed

wastegate diaphgram, might be torn. good luck

Kneale Brownson

You can try misting the wiring and distributor cap with a fine spray of water while running the engine in the dark and look for sparking.

Chad T

I had the same thing going on with my car and suspected it might be carbon build up as the ignition and hoses all checked out OK. I ordered some BG 44k to clean it out.

While researching the BG 44k I found that some people had used water to clean out the carbon. I decided to try it yesterday. I warmed up the car then disconnected the "T" from the vac line on the back of the manifold. I connected some tubing to the vac line and dipped it in to a jug of water. I would rev the motor a bit as it was sucking in the water. I only ran a little bit through as I was pretty nervous about doing this.

Took the car for a drive and couldn't get it to stumble/jerk/buck like it was. It would do it after the car was warmed up as the boost was coming on with a heavy load. Was the worst on the freeway in 5th gear. Tried to get it to do it on several full throttle heavy load pulls and was smooth as can be.

Boost comes on smoother now and builds to 1.9 on the gauge in 4th gear easily. (car is chipped with a 2.5 transducer so this would be 2.2-2.4 bar with a 1.25 correction factor.)

Try this at your own risk! I've heard stories of big chunks of carbon coming loose and getting stuck in the valves with water injection systems. I figured doing it at idle just reving enough to get the water through would be more gentle but you never know. I'll probably run the BG 44k through and maybe do a bit of the water again after everythig is softened up a bit.

Haven't done a lot of freeway driving yet but it seems to have helped so far. YMMV

Dave from Gig Harbor

I had a full throttle miss, and after replacing the incorrect wide rotor, and putting on a new cap, no more problem. Merry Christmas from another Salt Lake 200 20v owner.

snowchaser

an issue with carbon buildup? I never get beyond 1.6

snowchaser

Where in SLC are you? Let's hook up at some point as I have 3 of these cars.

Dave from Gig Harbor

Centerville and you have email on the way.

Chad T

Do you have a different pressure sensor installed in the ECU? Not sure what a stage 1 chipset consists of. Your 2 issues may or may not be related. Should probably do a leak test to make sure there are no air leaks. If the vacuum lines going to the back of the intake manifold are original they should be changed along with the vac line to the bypass valve and check the bypass valve itself. Also if you are above sea level you probably won't see as much boost.

The BG 44k stuff is supposed to work great for carbon build up. I ordered some on ebay. Some people swear by the water method and it seems to have worked on my car but there is always the risk of knocking a big chunk loose and damaging something.

Try this link for some tips on checking the vac hoses and bypass.<ul><li><a href="http://quattro123.com/200NoBoost.htm">http://quattro123.com/200NoBoost.htm</a</li></ul>

Suffolk

I like the wires in Kneale's list of suggestions.

A miss under load is usually the spark taking the path of least resistance.

Over time it will happen more and more, and you'll have to shift to 4th to make it happen less, taking "load" off the motor.

All plugs wires etc have a life of 100K or less.

-Scott by BOSTON