rpm fluctuating in 1st gear when cruising, any ideas?

[arronleeds]

if i try accelerate in 1st gear when im in traffic, if i hold a steady throttle below 2k rpm the car bucks and the rpm fluctuates up and down, is this normal?

 

[mty12345]

Doesn't sound it. I'd start by checking all the pvc hoses for splits and leaks, they can cause those sort of issues if they are allowing unmetered ar in.

 

[arronleeds]

Doesn't sound it. I'd start by checking all the pvc hoses for splits and leaks, they can cause those sort of issues if they are allowing unmetered ar in.

the thing is, my fuel trims are well within spec, short term is like -0.8 and long term fuel trims are at 1.6, ive changed the pcv and hoses, the diverter, the n80 valve, charcoal canister and the rocker cover gasket and its done nothing, even changed the spark plugs twice.

only thing i havent changed is the brake booster hose

 

[mty12345]

Oh right, in that case probably best to run some datalogs with VCDS or an equally capable scanner, and see if they show anything. If they don't show anything obvious and it's a direct injection engine, then possibly carbon build up on the intake valves.

 

[arronleeds]

Oh right, in that case probably best to run some datalogs with VCDS or an equally capable scanner, and see if they show anything. If they don't show anything obvious and it's a direct injection engine, then possibly carbon build up on the intake valves.

forgot to mention, had the car to r-tech, had injectors cleaned and also the inlet valves, no fault codes or anything, ive logged things like fuel pressure, misfires etc etc and nothing shows at all.

 

[rafletcher]

Why are you driving in first gear at all? Only time you need that is pulling away from a dead stop. Try using second and see if that cures your problem