Stuttering engine

[Tallulah]

Hi I have a problem, my golf is stuttering when under load, I was going along the motorway in 5th and as I started to go up hill it felt as if the car needed to change gear, the gear stick was rattling and the car felt like it was slipping backwards? I changed down and it still stuttered a bit but carried on up the hill. There no engine management light on the dashboard, it's just doesn't feel right. I had a new coil pack 3 years ago, the ht leads have just been changed as have the spark plugs as I thought it might be that? No4 lead looked corroded inside and no1 spark plug was a bit off colour.... any other ideas?? Could it be anything to do with the exhaust as I believe my cat will need replacing soon? Thanks for your thoughts

[SammoVWT]

If your cat is going, you will smell a nice eggy/suplhur smell. Its very distinctive. Plus if it gets to the point of collapse, you will find you will lose power - the car will seem sluggish and hard to accellerate, it may frequently stall.

I would have thought your emissions light would be showing though, if the CAT honeycomb hasn't melted together with a suspected CAT failure (which takes some doing).

It could be your coil pack if the damaged HT lead was driven on for some time. You would need a strobe kit to check for that I think. Someone with better expertise on this will hopefully be along to help you soon.

EDIT: Also when in doubt, codescan! Saves replacing unnecessary parts sometimes.

[Tallulah]

Replaced coil pack, took it for a test drive, a light came on as soon as in 5th under load. Read the fault code, intermittent misfire cylinder 1 & 4, coil open circuit, went into limp.mode. cleared the faults. Car drove fine, as soon as it 5th again with higher revs, limp mode came back with light, read the fault codes intermittent misfire cylinders 2 & 3, coil pack open circuit. Any ideas??? Car drives ok up to about 30mph then starts messing about.

[SammoVWT]

Does it happen at any particular rev range? Also what is the engine temperature like when this is happening? Is it the same warm/cold?

Does it happen at higher rev when in a lower gear, i.e. 3rd/4th etc?

Also do you have OE spark plugs fitted? Are they correctly gapped?

How soon were the plugs & leads changed with approx miles. Running rich or poor mpg? Brakes normal? no binding or hot alloys after a short drive? Battery ok? MAF connections are good?

Does gentle or hard acceleration change the stuttering? Does the stutter occur in neutral with some revs, or only ever 5th gear while on the move? Can you say hit 40mph+ in 4th with no issues?

It does seem odd. My first port of call would have been plugs/leads if a codescan came up empty.

It could be a number of things without more information, fuel filter/pump etc. Crank sensors failing. The more information the better. It just helps to build a better picture of likely scenarios.

[Tallulah]

Over the last 9 years, a question would be what hasn't been replaced on my car lol. Top engine rebuild, thanks to burnt exhaust valve seats on cylinder 4, throttle body cleaned inside out, only run on 97 fuel now, either esso or bp ultimate, belts replaced, battery fine, alternator replaced, new coil pack 3 years ago due to failure, it's been running fine until a couple of weeks ago when it startedhesitating, I noticed it first going up hill, looked at leads, corrosion in 1 so replaced, still had the problem, replaced coil pack, now the fault codes are showing!? It's when it gets up to 3000 revs plus, happens in any gear then but also noticed it stuttered in 1st this afternoon as well. Put the engine over 5000 in neutral, no code appeared. I pretty much know it's not an mechanical engine problem as it was all apart just over a year ago and the car runs really well apart from this intermittent fault, the idle is rock solid too. Not sure what to try next??

[Crasher]

Can we have the code numbers? The coil pack you have fitted, is it new, used and which make, part number etc, everything you know about it. I really hate to say this after what you went through a couple of years ago but with those first codes the second tool I would be taking to the car is a compression gauge.....

[Tallulah]

Hi Crasher, thanks for taking the time to have a look, much appreciated! 17757 was the fault code for the coil pack, I'll check the misfire code today. It's a new coil pack from Eurocar parts made by Haas, which is not the same make as we used 3 years ago, could it be this. If we do a compression test would a faulty coil pack affect the readings or is it a pure test of compression? Thanks again.

[Crasher]

17757 (P1349) Ignition output 2, open circuit
If this fault occurs, the engine control unit switches on the EPC warning lamp in dash panel insert

I would definitely start with a better quality coil pack, try to find a Bosch, Beru, Bremi, Delphi, Febi, Meyle, Hüco, NGK, or Valeo if possible, the Beru is my favourite. It would not affect the compression test.

[Tallulah]

Hi, we used a HAAS still having the problem - will try a new coil pack and see what happens, Thanks for your help and advice as always