Hesitation On Acceleration

[Peter67]

I noticed over the last couple of weeks a slight hesitation on acceleration when running between 30kph and 80kph (approx). Car seemed to be surging very slightly. This morning it was more noticeable and at one point there appeared to be very little throttle response when joining a motorway - actually thought it was going to stop dead. No warning lights or other symptoms and engine sounds ok no misfire etc. Had the supplying dealer stick it on OBD reader today and the fault "insufficient or low fuel system pressure" was all that came up? Its going in next week to see if they can get to the bottom of this but in my view it would be fuel pump / fuel filter related. Any views or history with this type of fault?

Peter

[Mybikes a cx500]

I think no-ones replied because your probably spot on, sounds like filter, pump, or the fuel line (perhaps check for a forgotten clamp on the fuel pipe...:)

Awesome looking car

[ColinBarber]

there are quite a few complaints about this on the US forums where the LS is more common.

Cures seem to range from resetting the ECU, using different oil, changing spark plugs, reprogramming the ECU to full valve or cylinder head replacement. This is a TSB on the subject, at least for US vehicles:

http://www.lambros.net/LexusTechInfo/2007LS/L-SB-0033-08.pdf

[Peter67]

Thanks for the advice. Interesting stuff for sure. My VIN is before those quoted in the TSB so could be applicable. Hope its not cylinder heads! I think the fault code seems to point in the likely direction as it "feels" like a fuel issue. I might do an oil change and pull the plugs to see what they are like - although it had a major interval service at Lexus dealer 10k kms back and they should have replaced the iridium plugs at that service according to the manual

[ROYT]

you could try adding some Redex injector cleaner in the tank first.

I use this about every third fill up,never had any fuel problems.

I had a Mark one LS I bought to rob for spares, after standing unused for a year the

fuel pump had siezed up, I stripped it and filled it with Redex on assembly, it never stuck

again.

[mr2lad]

I know this will sound stupid but I have heard that if fuel caps not on right it can cause fuel pressure probs... Worth checking