So i've had this car since 2005 and every thing is just well. just stepped over 120k miles recently

All of a sudden the car starts shaking as if its running on 3 cylinders. So i figured it was time to change the coil above the plugs. When i did, it was still the same. They were all firing enough power. All sparkplugs are good.

Something i've noticed is that when you start the car and keep on going, it runs smoothly no problem at all. I can even go around 100 miles no problems at all. Once i stop at a traffic light, it stays calm, all of a sudden the ideal rev goes slightly down and the car starts shaking, very low power. I have to turn the engine off, count to about 10, turn it back on and runs smoothly again. leave it ideal and it starts shaking again. The only solution i could find to the stopping at traffic lights problem is to keep my foot on the fuel paddle to where the rpm gauge stays on 1500rpm or slightly higher, not less.

has any one got any advice for this problem? Any thing appreciated

Edited 24 July, 201412 yr by EdmundB

Welcome to the Forum.

When you say that the spark plugs are 'good', are they new? - old plugs can look OK, but fail when in the engine.

It might pay to buy a tin of 'carb cleaner' and clean up the throttle body.

I would suggest that you get any fault codes read, but it is better to clear any old fault codes that may show up, run the car and re-check for codes, any that show up then will be the current ones.

Regards

Welcome to the Forum.

When you say that the spark plugs are 'good', are they new? - old plugs can look OK, but fail when in the engine.

It might pay to buy a tin of 'carb cleaner' and clean up the throttle body.

I would suggest that you get any fault codes read, but it is better to clear any old fault codes that may show up, run the car and re-check for codes, any that show up then will be the current ones.

Regards

- spark plugs are brand new... but i've walked like 10k km with them while the car was shaking etc

-so I've tried cleaning the throttle body using a guide from this forum with a carb cleaner. this thing was full of shit. never had it cleaned since i owned the car back in 2005. here is a picture of it at the 5th wash. half the carb cleaner is gone.

some local shop here told me to try oven cleaner foams. it works faster and makes all those solid black bits of oil and fuel gewy and easier to clean. so now it looks like this

after installing, i tried resetting the ECU. unplugged battery for about an hour. ran the car and it started at 1500-1300rpm or so. some smoke coming off the back of the car that quit. i guessed thats the carb cleaner when i cleaned the drain of the throttle body. after 30 minutes no paddles pushed. Then i turned it off and on again, the EPC light is still on... and adding some rev doesnt work. if i step on the gas paddle, nothing happens... no rev.

Any thoughts?

I'm not sure what you mean with fault codes. could you explain more?

The throttle body certainly LOOKS better!

The thought just crossed my mind that I hope you didn't get any of the oven cleaner inside the electrical part of the throttle body.

Fault Codes:

When there are problems with the cars electronics, codes are stored by the Electronic Control Unit (ECU), by plugging either a code reader or a special lead which connects to your laptop (used in conjunction with software) - (have a look at the Ross-Tech website for details) you are able to read these codes and, depending upon the software, make certain adjustments to the engine.

The code reader (or the special lead) plug into the diagnostic socket of your car.

With a basic code reader, you will be able to read any codes that have been thrown up, and with all but the very basic ones, you will be able to clear the codes.

You would probably find a connection cable on E-Bay, but some of these may be of better quality than others.

One tip that I would give you is that, once you have your code reader (or whatever) make a note of all the codes that are shown - some of these may well be old ones that no longer apply, so, once that you have made a note of them, DELETE all the existing codes.

Run your car for 'a while', and check for codes again.

Whatever codes are there at this stage are the ones that are causing current problems.

Regards

ehh.... a bit might have gotten into the plug... but not the electric body.... unless the electric body is not sealed well? still haven't connected my battery since yesterday. Has any one got a good definite guide on how to reset the ECU on the 9n 1.4 16v?

gonna check the codes and get some knowledge about them. any link you recommend for ross tech guys?

appreciate your response really ^_^

I've tried resetting the ECU by unplugging the battery for a whole day. the engine goes around 1100 rpm but after, will refuse to add any rev when i press the paddle. and its very shaky. any one advise?

Edited 29 July, 201412 yr by EdmundB

disconnecting the vattery will only erase the short term memory. and will do very little until you drive 60 k/m (afaik) you need to connect a code reader to first read the codes and then delete and recheck later(as above)

I'm willing to bet there is a lambda sensor code on there, as these are not normal lambda sensor and they widely effect the idle.

does the accelerator pedal work if you press it right after starting?

as above also, these engines love new plugs, more then most others so even if they look okay they should be changed regularly.

i remember when i had my 9n3 i have a full set of plugs, coils and tools in the spare wheel well as its all that ever went wrong with it :)

disconnecting the vattery will only erase the short term memory. and will do very little until you drive 60 k/m (afaik) you need to connect a code reader to first read the codes and then delete and recheck later(as above)

I'm willing to bet there is a lambda sensor code on there, as these are not normal lambda sensor and they widely effect the idle.

does the accelerator pedal work if you press it right after starting?

as above also, these engines love new plugs, more then most others so even if they look okay they should be changed regularly.

i remember when i had my 9n3 i have a full set of plugs, coils and tools in the spare wheel well as its all that ever went wrong with it :)

Thanks for the reply.

i have drove around 100km with no luck. I'm gonna read more about this code reading faults. not really a mechanic nor an car electrician. not sure how i can do all that.

The accelerator pedal works well if i press it immediately after starting yes. When i start, it goes around 200-900rpm willing to stall. then settles at 1100 where the pedal will not do much. stepping on it makes rom jump from 1000 to 1200 and goes kinda shaking. I've changed the plugs with new ones with coils just weeks ago.

I've read somewhere that on the 2005 mk4 1.4 engines, you cant reset the ECU by unplugging the battery off. Some VAG-COM software and so....

gonna have to read on more about it. Appreciate your reply!

there are cheaper versions of vagcom on ebay etc which will do many things, but will not alloe you to make changes etc. this will do for your situation, its pc based and plugs into your usb port and connects to the car. its very straight forward to use and will deffinately come in handy in the future. search for vcds on ebay, last time i checked they were around £15

if you go for a handheld unit then make sure it can be used with vag cars as some dont

where abouts are you located? if your local then I'm happy to help out and have the full version :)

Have a look at eBay.co.uk item code 161380482897 for an example of a vcds or vagcom cable. You'll see they are relatively cheap.

For some instructional guides see http://www.vagcom.co.uk there is a section on application there.

Anyway, I'm not sure on suppliers in Saudi but best of luck!

PoloD.

so here i am. d4ove around 200km. I've noticed the car behaves when cold but when warm, it sticks to 1200rpm and disables the thottle paddle. this happend a couple of times mid way driving. it completely disabled the throttle paddel and drops down from around 3000-3500rpmto 1200. pressing it makes the rpm keep jumping from 1000-1300. the exhaust smells full of unburnt gas... lots of it.

causedme alot of ailliness so far....

Got given my 2003 9n (1.2) last year which was in similar shape to yours. I was getting the same engine wobbling while idle, varying idle revs, sudden loss of power.

It turns out that the ignition coils were all completely different, and only one was actually working properly, so I'd probably start there, but I also replaced the plugs, old gaskets, dodgy water pump, air filter (and some other things that all needed doing) and it's good as new now.

so I've changed the temp sender. things look a bit more steady but not yet enough. the throuttle body still refuses to respond. a friend of mind told me to clean the air sensor in the throttle body. i cant see to find something like that, any one can reference me? I've uploaded pictures of the upper and lower side of the body plus the intake under it.

when i was looking for the air sensor on the throttle body, i found that the body's ecu plug was full of oil. where did the oil come from? using the oven cleaner, it leaves a bit of oily lubricant if yiu dont clean it with a peice of cloth or so. so i went and got my self a contact cleaner spray full of alcohol apparently. did a good job and now pressing the paddle works !

when i first put the battery on, the throttle body made some sound. opened up fully and back closed. something that never happened before.

the car is still shaky when idle. I'm thinking the sparkplugs need sleaning after a month of testing and gas smell. any thoughts?

i should have listened to Caretakerplus when he told me off about the oven cleaner and the electric parts =(

ok so this car's problem is officially solved. you guys were right, i needed that plug and vagcom software to align the throttle body. i went to a local shop with a young man thats been working for the dealer for 10 years. he says all the steps that I've done so far were good and make sense, only i didn not align the throttle body with VAGCOM so i owe you all that. with a couple of diagnostics, he claims that other shops were trying to rip me off saying the engine has only 3 cylinders working and it needs a while new engine. the car is way better but its shaky a bit so we ran a few tests, checked a couple of places behind the engine and discovered a small crack in the intake manifold i made by mistake one day when i was changing spark plugs and dropped a wrench or something. the crack is soooooo small i can barely believe its causing any air leakage. so we tested an old manifold he has on his polo and every thing went fine.

its time to change lots of stuff... timing belts... a/c compressor... this is gonna burn a hole in my wallet but at least i got my polo back. long live VW

Thanks every one!

Edit: oh yeah, the EPC light went off too ^_^

Edited 24 October, 201411 yr by EdmundB