Hi all,

My car is a stock series 2 manual EL XR8 sedan with a 3" exhaust & has high kilometres.

At light throttle openings (ie: putting around town) she feels as though she doesn't have enough fuel one second followed by way to much fuel the next. Trying to drive calmly in 2nd or 3rd gears sees her kicking & bucking & kangaroo'ing like the worst learner driver in a manual car could muster !! A slight increase in throttle opening feels as though something kicks into action & away she goes including tyre chirping if I'm going around a roundabout .

At 80km/h & over, she starts to clear up & run fine & then stutters & stammers again when the road speed drops down & at idle, the richness of the exhaust fumes near on makes my eyes water & this is when she is warmed up to operating temperature.

The car has a brand new fuel pump & filter as I thought this was the problem & after that not fixing it I swapped throttle position sensor & airflow meters & still no improvement !!

Just wondering if anyone else on here has had this drama with their 5.0L E series & how do I go about fixing it ?!?!?! . . . . local workshop is saying she will need a complete fuel system clean !!

Is the MAF plugged in? - upstream from the Air box?

Also perhaps the TPS Sensor - but so far these are only educated guesses

Did you happen to swap the Fuel lines over by accident perhaps?
Does the Fuel Reg still have its vacuum line on it?
Is the PVS Valve at the back on the inlet manifold still in there?

Try these in this order

Do a self test, KOEO & KOER including cylinder balance. Fix any faults.

Unplug MAF and take it for a drive. If it runs better like this, clean the MAF hot wires then reconnect and drive. If cleaning doesn't work, try a known-good MAF that has been cleaned.

If unplugged MAF doesn't improve, then try cleaning ISC. It may be sticky. If cleaning doesn't work, unplug ISC while idling. If the engine doesn't die, replace the ISC

Set TPS voltage to 0.80 - 0.90V with engine running at idle. Make sure TPS voltage rises when you open the throttle (do this with ignition on but engine not running)

Measure fuel pressure with vacuum hose off engine running. Should be 39psi

If it has a big cam fitted, it may need a tune on a chip. My AU2 XR8 has a cam that's a bit too big for a stock ecu and it bucks below about 1200rpm