win72010

Ok so silved2 we are talking same language. If you read my posts I make it clear that first priority is correcting missfire. Number one problem with a mostly smooth and responsive pre facelift 4.2L engine that codes with multiple misfires is WRONG PLUG and or gap. The 5v engines came with bosch plus4 open gap not able to gap type plug great plug if the coil is designed to fire it. The 4v engine came factory with standard type plug gaped at .32 The old style coil with seperate output stages are designed for that plug type. I have personally pulled bosch plus4 with less than 2k miles on my 98 A8 and replaced with the NGK Platinum gaped to .32 and solved multiple random misfires. Also my sister bought a 97 A8 and had the NGK Platinum installed that I recomened to her. She had mostly smooth running car with multible random misfires she hardly noticed anything. I drove the car and knew something was off. So I Ran My ROSS TECH and confirmed issues with misfire. Pulled the plugs and the gap was .45-.5 That is like running old worn out plugs. Needless to say that mechanic in Indy was either lazy or did not know correct gap. Car is smooth as silk now. Use good old fashion vacuum gage and do some testing. A problem cam timming will be very obvious and have less than 11 or 12 inches. your car with proper plugs and gap should give 15 or 16. cuz you have 190k miles maybe even as low as 14 inches.

As for the old fluid is the "glue" makeing an old tranny work...crazy. lets agree to dissagree. The point of drain and fill first and then filter change is the end result is much improved final fluid quality. Drain and fill 50+% fluid change. Any junk lossened by new fluid will be caught by trans filter and further clog. I would recomend maybe two or three thermo cycles cold to fully warmed up then filter change. Now you have new filter with more than 75% new fluid. Just a drain and fill is likey to damage a high mile ZF5HP24A we both agree on that point. You will still have clogged Filter and Free metal shavings are not going to be caught by magnets that already look like a chia pet. I have recomended going to Paul W's audipages.com more than once PRIOR to attempting filter change. If you read his account of limp mode car becomeing drivable after filter and fluid change. You will see the magnets. Do you want your high mile car having free metal shavings like that? Along with clogged filter? LOSS of fluid pressure as a result of clogged filter will cause all kinds of hell. Incudeing slipping in general and frying cluches, delaying of lockup etc. Witch I believe could be the shaking darrolljr00 describbed. Just know that the filter is also the trany fluid sump pickup. Even a dent in the pan could effect sump pickup. Some ZF gurus recomend removing 1/4 inch from sump tube on filter (not me). I have personlly changed the fluid in 6 ZF5HP24A tranys in the last 2 years and also complete rebuild of the valve body in one of those cars. I believe my way of fluid transfer is far superior to what Paul W recomends on audipages.com. That said I agree that car must be stone cold when you start process of filling. I recomend with the car on all fours and engine off. When the fluid starts to overflow tower...then it is time to start car and run through gears, then fill some more and repeat until your are confident of stable level. From the time you start cold car till the time you replace the tower plug should be aprox 10 min to 15 min. This recomendation is in line with Paul W's and ZF's target fluid temp. If you error... error on fluid too cool. That would result in slightest overfill. If you read Pual W's work on audipages.com he has car on 4 jackstands cuz his marine type fluid pump tansfer requires the elbow room. FAR MORE tedious and dangerous. let alone trying to level car with 4 jackstands. All four tires on level garage floor and pumping fluid safely from beside car...seems like no brainer when you compair the two methods. Keep it simple and safe. One thing we all agree on...Audis are sweet ;-) darroljr00 please keep us posted on your car

silverd2

Granted, timing belt jump "usually" happen on one bank. If improperly installed and cam indexing on both sides, then that's another story...I've seen some pretty stupid moves made by even Audi certfied mechanics at dealers abd indy-shops. All things are possible when it comes to incompetence.
The poster here has no history, other than what he was told...recently installed timing belt...car sold for only $1K. Well, I was just guessing that even the dumbest of sellers would try spark plugs to double the price of the car, if it could make it run smooth.

Who knows? ...only time and the discovery of the source of misfires will tell.

By the way, I filled my atf cold till overflow, then started engine, gears, etc...on level ground with a gravity feed I set up (no pump needed)...no jack stands...Also followed a combo of ZF factory and Bentley instructions. Everything important is basically exactly the same as AudiPages: Level car, correct temp, gears, overflow, etc....6 of one, a half dozen of the other.

On leaving a working (if it is?) high mileage trans alone: From a guy who's probably forgotten more than you and I put together will ever know about these trans's..a man of few words, but endless talent & knowledge about these car (esp trans) ..and NOT a proponent of changing atf in high mileage trans's (esp with unknown histories). J

Just a couple of hundreds of examples:

Post # 5:
https://www.audiworld.com/forums/sho....php?t=2817845

Post # 11:
https://www.audiworld.com/forums/sho....php?t=2817253

darrelljr00

Here is a video of my car.. I replaced the transmission fluid and new filter.. Car is still shaking.. I shot the video while i was driving .. The shaking begins at 2 minute mark

http://www.youtube.com/watch?v=m_QpK...ature=youtu.be

silverd2

Myself? ...I'd (if safe, without traffic) shift into neutral during the shaking, to see if it's suspension related. Also on and off the gas during shaking, to see if it's torque load sensitive (engine or trans?).
Plus you really need that check engine light working (sounds like it's burned out), to see if it's flashing during shaking, which could indicate a current severe misfire.

90SQ

My '98 started with random misfires and now is doing the exact same thing, but mine came to this gradualy.

I replaced with no effects:

-spark plugs
-spark plug tubes
-fuel filter
-had p0321: engine speed sensor: replaced


Now i suspect the fuel pump as it only does it under charge, checking pressur today, will keep you posted.

90SQ

Well, fuel pump is fine: 57psi so i pulled the fuel ramp to see how the injectors were spraying and.......ugly sight:

1 had nothing comming out and the rest of them are not nice at all. I suspect the last owner used 87octane gas instead of 92-91 octane as recommended. Do that for 200k miles and this WILL happen to you, i mean.....if you dont have any money to put good gas in just dont bother buying an A8, go get a civic or somcrap!

SO:

Going to get them cleanned up at a performance shop in town today, will keep you posted.

win72010

So the simple sweet truth is many heads beter thane one. I was looking for faceplate to install install double din in my 2000 A8 and ran across Darrolljr00 post. I have never felt compelled to post before. I remebered buying and then driving my 98 A8 60 miles home with one output stage gone. Dumb thing ran terrible during "Load" on engine and at 60 mph on level strech of road...almost smooth. Lean into gas and vibration...same at any steady speed. light throttle almost good...then load and vibration. Under normal load of exceleration he would have rough running engine. After rereading earlier posts and seeing the video... clear not same problem. Part of the reason I am glade we are beating this misfire topic to death is...I wish I had solid info on a propely identified topic. It is my hope that many will find value in this thread and save some money. That said this is not a properly identified post/thread lol. Gap your NGK v power plugs to .32 (good choice for 4valve 4.2L) and I believe minor issue of missfire is solved. Remember I had otherwise smooth running 4v car that only showed codeing when I hooked up my ROSS TECH. No Check engine light! Confirm status of check engine bulb by simply turning on ignition without starting car and and look. As far as timming belt as being possible issue... not likely from what I see. Just know that I do not use any special tools when doing TB service (both 4v and 5v 4.2L). I use old school method by pulling valve covers and timing cams in a way that could result in several degrees plus or minus slightly advanced or retarded. It is literally not possible to get one bank to jump tooth on cam gear and still run. Because the cam gears are not keyed, they could be slightly advanced or retarded and run "good". That issue is best checked with vacuum gauge. Thats a whole new topic. darrolljr00 needs new post..his problem is occuring at torque lock up I still strongly suggest my earier post as valid. I strongly suggest investing in ROSS TECH for anyone who owns any Audi. I have no affiliation with them just believe it is the most cost effective way to enjoy the Audi experiance :-)

jameslattimer68

Had the same issue but in the opposite way under 65 mph the car was shaking; not like falling apart but between 50 and 60 mph felt almost like that, when I went over 65 mph the car went very smooth, was odd never discovered why it was doing that. Sold it two years ago but I am curious what might have caused that.

darrelljr00

1. When the car starts shaking.. shifting into nuetral and the shaking immediately stops.

2. 1 lead on the Ignition control module/power output stage shows an open lead. So 1 module is bad..

3. I noticed what i believe is a vacuum leak on the plastic "T" fitting that I THINK plugs into a fuel injector housing..

<center>
<a href="http://s289.photobucket.com/albums/ll216/darrelljr00/Audi%20A8%20suspension/?action=view&amp;current=eedd2458.jpg" target="_blank"><img src="http://i289.photobucket.com/albums/ll216/darrelljr00/Audi%20A8%20suspension/eedd2458.jpg" border="0" alt="Photobucket"></a>
<br/><br/>
</center>

4. I will regap all plugs to .32 today and replace the "T" fitting today and return the results..

5. These are the initial obd readings from a regular scan tool i received 2 weeks ago. (before spark plugs/ coils)

*** p138 long term fuel trim add fuel bank 2 system too lean
*** p0455 evapp emission system leak (detected gross leak, no flow)
*** p0300 Random misfire
*** p0304 misfire cylinder 4
*** p0305 misfire cylinder 5
*** p0301 misfire cylinder 1
*** p0302 misfire cylinder 2
*** p0307 misfire cylinder 7
*** p0501 vehicle speed sensor range performance


Thanks everyone for contributing your advice..


ALso @ win72010 I read that you still think it is torque converter locking up that is causing the extreme shaking.. Please explain

that_tg

Not sure if my advise is even worth two cents. I am going to add my 1.5 cents of advise.
Check the timing. That was one of the first things mentioned and it is what I keep coming back to on your misfire issue. Second, The axles with the torn boots. They could have been like that for the past 10,000 miles. That is what I would change to fix the shake when driving in gear.
Save your money and time. Buy new axles from ebay (43 bucks each, free ship, no tax). I bought one from ebay and it was great. Decided to replace the other side at the same time and did not want to wait for it to be shipped. Off to Autozone I went (76 plus tax). What a piece of junk. Poorly rebuilt and sloppy. Returned it and went back to ebay.

Great buy on that car! Hope you can get it back to a smooth runner. The people here are the best, and will help you all the way.