What could be wrong with my car?

pazza2000

Hello,

Looking for some basic advice and thought it could possible be found here instead of looking further afield. Very recently purchased a 2nd hand car from a Garage(Audi A3), days after taking receipt(after a service/MOT from the garage) it had a problem with the Radiator fan which would not go off although has now been fixed.

Possible not related to the above however now having barely had it back a week, I am noticing that the engine is pulsing/reving sporadically.. at first i thought it could be my driving however it is not, and I think it is getting worst. When the engine is in neutral, or idle at first it rev's you can see the dial ticker bobbing up and down slightly and you can here/feel the revving outside of the car. It also happens when you are driving at a fixed speed or occassionally when I am in lower speeds. You can actually stay at 60 and watch the ticker bob up and and down and feel the car ever so slightly accellerate, slow, accellerate, slow.. it jutters basically for want of a better word.

Anyway, the car is under warranty however before I call the garage i want to know what i am talking about, I am poor with terminology and suspect if I know what i am talking about they were more likely to do the job and fix it right -I feel like I have bought a timebomb. I also notice it rattles slightsy when I go over holes(rattling sound coming from the back), I know it is a second hand car although surely having had an MOT and service this would have caught it -would this be the suspension?

Thanks guys

passatrider

You have a warranty so take it back to be repaired. Give them a call and let them deal with it.

vikingaero

The engine problem could be anything - air mass meter, idle control valve, but it sounds like the exhaust gas recirculation valve is iffy, the list is endless unless you get it hooked up and looked at.

The rattle could be suspension bushes, loose anti-roll bar mountings, or maybe a simple exhaust hanger has broken. The MOT guy wouldn't hear the rattle because the car is tested statically on smooth rollers.

Strider590

pazza2000 wrote: »

Hello,

Hi

pazza2000 wrote: »

Looking for some basic advice and thought it could possible be found here instead of looking further afield. Very recently purchased a 2nd hand car from a Garage(Audi A3), days after taking receipt(after a service/MOT from the garage) it had a problem with the Radiator fan which would not go off although has now been fixed.

When I had my Peugeot years back, the fan would stay on constantly.... I eventually found out that it when the aircon is on, the fan stays on to cool the heat exchanger.

pazza2000 wrote: »

Possible not related to the above however now having barely had it back a week, I am noticing that the engine is pulsing/reving sporadically.. at first i thought it could be my driving however it is not, and I think it is getting worst.

Not related, maybe related..... Diesel or Petrol? Could be an EGR fault, a dle valve fault, and a couple of other less likely things.
Possible lambda sensor fault, which would also cause over heating (Fan ) and if the trainee mechanic couldn't figure it out, he might of disabled the fan altogether which would cause more over heating and exasperate the problem.

Does the cooling fan still kick in if you leave the car standing with the engine running? (should kick in before 95 degree's!!)

pazza2000 wrote: »

I know it is a second hand car although surely having had an MOT and service this would have caught it -would this be the suspension?

Usually a worn bush on one of the control arms, or simply knackered shock absorbers. What's the mileage? if low then i'd say it's been driven by someone who didn't give a hoot (like a boyracer or sales rep).

Service/MOT does not mean a car is in top condition, it simply means it's not going to come of the road and slam into a bus stop full of people all on it's own.

If it was MOT'd by the selling garage, they probably didn't even test it, they're not going to want to find costly problems because it eats into profit! (they just want a fast sale).... They get away with it because people assume the MOT means the car is fine and they carry on regardless (turn the radio up) until the next MOT where it fails outside of warranty.

pazza2000 wrote: »

Thanks guys

:T

cyclonebri1

Take it back, they will run a diagnostics check on it

As said it could be one of a dozen or more sensors most likely.

pazza2000

Firstly, thanks for the replies.

I do not believe it is a sensor, the engine is revving. When it is idle, it drops below 1(1000rpm) which I know is not normal, and occassionally you can visibly see the rev counter jumping up and down -which you can hear in the engine. When also sitting at a flat high speed you can see and feel the rev counter/engine pulsing. It sounds like its gasping, not too bad... although as the driver, you can tell(passengers less so) and the fact that it happens occassioanlly tells me it is a problem. Did not have a chance today although wil call first thing mon morning. I agree with the sugestion that the garage wanted a fast sale and did the basics to it, and not a full service... this is why I wanted to call them and give them suggestios as to what it could be, sound like I know what I am talking about so that they would be less likely to fog me off as someone who knows sat about cars. Truth be told I want to take it back... its an 05, 60k miles A3, from a decent garage. 2 days after having it I had the problem with the radiotor fan not going off at all(had to disconnect the battery) which they have now fixed, had it back only a week and now this problem, albeit minor but I know it has the potentil to turn into something worst. Also, they said they would put it into a full service however I can hear a slight rattle going over bumps, and the back passengers seat overhead light needsa new bulb... am I being too fussy expcecting these minor concerns fixed/replaced??


Apolgies for poor grammer. It really is a dampner for me to have to address another issue with this car.

Thanks guys

cyclonebri1 wrote: »

Take it back, they will run a diagnostics check on it

As said it could be one of a dozen or more sensors most likely.

It was not an Audi garage I bought it from

Rossy.

A car idling under 1k is perfectly normal

Most cars idle between 800-900 rpm

The fluttering of the rev gauge/engine speed will almost certainly be either the idle control valve, or the mass air flow sensor (MAF)

If you take the car back and ask them to connect it to a diagnostic machine, they will be able to find out what sensor is faulty

Car's rattle over bumps over time/age/mileage etc, it is probably a worn bush or something - A bulb is a couple of quid max also

Kilty_2

Some cars will vary the revs slightly at idle when the outside temperature is low..... Not by much though.

ScoobySnacks79_2

I would agree, the most likely causes for this fault are, in descending order, mass air flow sensor, lambda sensor or throttle position sensor. I'd rule out the idle stepper, as it happens at higher revs too.

My little fiat idles at about 700 rpm, I don't know of any modern car that idles at anywhere near 1000rpm!