Hi All,

Long time reader but can't remember posting.

I was on my way home from holidays today towing a boat, about 40 mins into the 2 hour drive, the car starts to surge and loose a lot of power on the way up a hill at high revs. All of the way home I had very little power, every time I tried to accelerate it would surge, I had to nurse it all the way home using very low revs and dropping down a gear each time the problem occurred. The fuel gauge showed that I only had around 1/4 of a tank left although I had just filled up, after stopping for fuel (which only needed 15 litres to fill up again) the performance improved, but ended up getting around 30 mins later.
When the problem was at it's worst, it was very hard to move from being stopped.

After getting home and removing the boat, it drove a little better although if I floor it, it just dies and only goes if I accelerate slowly, will only rev up to around 3-4000 RPM. Was reading in the forum how a bad battery can cause this, but the battery is only around 6 month old.

It is a 2003 TJ sedan auto with the 3.5, I am suspecting the fuel filter and intend to change it tomorrow morning. I would like to hear other suggestions if anyone has any?


Thanks,
Vos

Hmm, fuel pump issue in that the float with the intake attached has broken off or stuck high and with the extra down force on the rear with the boat exposes the intake more often and/or sooner.

Edit: it could be the filter but then again, it shouldn't have made a difference whether towing or not. It is not as if you were gunning it and the fact your fuel gauge showed low on fuel points to the float.

I will add that after filling up with fuel the performance improved, but the problem was still there, just not as bad, although I was weary to gun it in case it made if worse again. I filled it up again after getting home and drove it without the boat, when I floored it with the full tank and no boat it just died and I still have to accelerate slowly to gain speed.

If it was a dirty fuel filter then the level of fuel shouldn't make a difference but you said performance improved after a refuel with boat attached but problem is still there without boat but full tank. Replace the filter first as that is cheap and if that does not resolve the issue then it is the intake.

Put something heavy in the boot and back seat and test if you have the time.

Where do you normally go to fill up? I have never replaced the fuel filter in my petrol cars and my 1995 KS Verada V6XI had almost 200K KMS.

Thanks for the reply Vlad, I will go ahead with the filter first and see how it goes.

Cheers,
Vos

If the engine spins up ok with very light throttle but staggers or dies with a bit more welly, these are classic symptoms of a dodgy coil. From experience they can go suddenly with little or no warning.

Damn I forgot to mention that the engine warning light was also on sometimes and off other times.

I took it for a drive this morning and it was working perfectly while it was cold, as soon as it heated up to problem recurred. Would it do this with the coil also?

I think that when I stopped for petrol it cooled down slightly and went better for a while then gets worse as it get hotter again.

Thanks for the replies I have had so far.

It idles very low when it is hot also.

ISC issue? PM Madmagna and see what he thinks.

It is well overdue for a service anyway so I think I will just book it in and get it done next week, I will report back with what the problem was.

Thank you everyone that posted suggestions.

Check your air filter.....
If fouled it can give the symptoms you describe.

If the engine light came on there might be a diagnosis code to read. The service centre will read them anyway but in case you want to know yourself the diagnosis code retrieval process is below:

http://i63.tinypic.com/raol8g.jpg

12 Air flow sensor system
13 Intake air temperature sensor system
14 Throttle position sensor system
21 Engine coolant temperature sensor system
22 Crank angle sensor system
23 Top dead centre sensor system
24 Vehicle speed sensor system
25 Barometric pressure sensor system
41 Injector system
44 Ignition coil and power transistor unit system
54 Immobiliser system
61 Communication with A/T-ECU system <A/T>

Put the car in for a service and it turned out to be a loose connector on the air flow meter.

Thanks to everyone for their suggestions and the information.

Why would a loose AFM connector affect fuel level in tank?

Why would a loose AFM connector affect fuel level in tank?

Logically, it can't.
They may have found a loose AFM connection when they looked at the error codes (12 and 13 I presume) which, when fixed, would have fixed the surge problem, but the fuel gauge reading inaccurately may be a separate problem unrelated to the MAF.

I'm also surprised at this outcome. When the ECU can't detect the MAF's reading it uses failsafe data and the engine runs fine, albeit VERY inefficiently. I agree the fuel gauge thing must be a separate issue but I'm not convinced a disconnected MAF would have the effect the OP describes. But I could be wrong ;)