3.5 EFI missfiring/surging while in low range

[fnukle]

1988 3.5 EFI Flapper
ZF Auto, LT230
Rear Maxidrive
Drives great in high range never a problem.

Hoping someone has come up against this one before heh.
This issue started awhile back originally while doing really steep climbs.
Has now pregressed to major surging while stopped or nearly stopped in gear. Its really trying to drive even on the flats but only while in low range.

Have replaced the fuel pump and leads, dissy caps etc to rule those out.
I'm assuming its a loose wire somewhere, to do with the transfer case?
Possibly the coil tho i dont see why it's fine in highrange.. :S
Ideas? Please :)

[fnukle]

Just found a thread I must have missed.http://www.outerlimits4x4.com/ftopic138764.php
A likely cause below:

Thanks for the info Rovernaut

I recently had the same symptoms, tried all what you have done and still no good.
Turned out intermittent sticking of the exhaust valves . Also if the valve face is not seating in it's seat and not sealing , then exhaust gases leak past and result is loss of power is not sealing .
I found this under load trying to get up hills

I took heads off , had the heads pressure tested, heads rebuilt, faced etc. new stem seals
New head gaskets, head bolts, cost me all up about $1100 with me pulling the heads off and the reinstallation.
Instant power gains, drivers like new now.
Karcraft in Sydney, do mail order, good source for Rover parts, got all my gaskets there, they have many genuine parts/ or OEM manufacturers parts. Got my stuff there very happy and quality very good

Possibly this is due to low oil pressure/ low quality will flush mine out see if that helps at all. Likely wont fix the issue but will try before ripping the heads off.

[Rovernaut]

1988 3.5 EFI Flapper
ZF Auto, LT230
Rear Maxidrive
Drives great in high range never a problem.

Hoping someone has come up against this one before heh.
This issue started awhile back originally while doing really steep climbs.
Has now pregressed to major surging while stopped or nearly stopped in gear. Its really trying to drive even on the flats but only while in low range.

Have replaced the fuel pump and leads, dissy caps etc to rule those out.
I'm assuming its a loose wire somewhere, to do with the transfer case?
Possibly the coil tho i dont see why it's fine in highrange.. :S
Ideas? Please

[fnukle]

Sweet just got back from the local testing ground in Sumner park.
Got it sussed, however embarrassingly was the AFM :)
Quick Video of the beast from yesterdayhttp://members.iinet.net.au/~lomu/rangiejump.mpgRight Click, Save As

Dropped the engine oil,
filled with new stuff +nulon engine flush,
Idled for 15 minutes,
dropped oil again
Filled back up with new oil.. again.

While I was filling that up I started checking the engine over again, pulling and prodding everything when I pushed on the AFM the engine idle dropped and started surging....
I found the inlet pipe(from AFM to Inlet) was loose.

Honestly the ammount of times I've checked the AFM is a bit frustrating however glad its fixed. [/url]