I drive a 2004 BA XR6T manual with a couple of mods on it and I'm at a bit of a loss as to whats causing my problem.

 

Very occasionally, usually on a hot day, my cars throttle response becomes piss weak in the low rpm range after driving it a bit hard, almost having to put my foot on the floor to get the car rolling from a stop as I bring the clutch up. It surges when it gets to about 2300rpm and the throttle becomes responsive and drives like normal until the revs drop below 2300 or so, so shifting gears when driving regularly feels like I'm driving a slug.

 

The reason I'm at a major loss is that I can't seem to recreate this issue consistently, the throttle is always crisp when I start the car up for the first time every day. I always let the car warm up and give it a good drive before I thrash it but this issue seems to come and go. The only thing I could think of is heat soak... the coil packs and spark plugs were replaced when the car got tuned and its been happening since then.

if it happens only after driving it a bit hard, it's probably the valve springs going soft... but the symptoms wouldn't last for ages afterwards.

 

Valve springs makes absolutely no sense at all for the symptoms he is experiencing.

driving hard and then throttle response issues is definitely a possibility.

 

what's your idea?

The fact its at low revs after a bashing would kinda rule out valvesprings yeah? If the issue was at high revs id 100% agree with springs being stuffed.

 

What mods have u got?

It sounds like a fuel issue to me, did u upgrade the intank pump? 

when you fatigue the valve springs, you get rough running after you thrash it. Sometimes you get top-end drop-off in power during the thrashing, but the obvious symptoms of valve springs is afterwards, not during, most of the time.

32 minutes ago, BAXRTUTE said:

The fact its at low revs after a bashing would kinda rule out valvesprings yeah? If the issue was at high revs id 100% agree with springs being stuffed.

 

What mods have u got?

It sounds like a fuel issue to me, did u upgrade the intank pump? 

Ive got a walbro 340 255 and 650cc injectors as well as plazmaman valve srpings, I'm thinking about taking it to get the codes read and see if anything comes up?

Whats the full list of mods?

The tunes max psi?

U mite have a dud injector, have u checked if they are all pulsing? 

It mite be a hose connection in the tank?

Im def running with fuel issue though.

@Puffwagon @JETURBO @Ralph Wiggum mite have some clues??

were genuine coils used when they got replaced?

 

I ran vdo's fine though...

I don't think it's springs or fuel as op didn't mention it chugging and the car runs normally over 2300rpm.

 

It needs to be scanned and data logged to find out what it's doing. 

 

Luke and Aaron would be the guys to ask though, they've been tuning these cars longer than I have.