My 97 Range rover 4.6 had a cracked manifold, put on a set of extractors professionally(as they were a cheaper replacement).The catalyctic converter was bypassed. Have since experienced rough Idle, overfueling(smell), A flat spot at around 1800 revs and general power loss. I have no errors showing on dash or on diagnostic scan. We thought that after 200 kms or so any resetting due to the extractors would be done, but so far 500kms and if anything the idle , flatspot are getting worse. Any help or ideas appreciated.

 

How are the O2 sensors handled? Perhaps they (or lack of them) is causing the rich condition. Guys who race cars the are somewhat modified use an O2 "imitator" that fools the ECU into thinking everything is fine. Clean IACV and MAF with proper solvents when stone cold? All cables hooked back up to these devices?

 

The 02 sensors are intact and are not showing up as a fault on the nanocom evolution tool. No codes at all showing up. I will clean the bMAF and the IACV tomorrow and let you know the result. Seems to be worse when warmed up,at idle and when changing to 4th gear at around 1700 revs just labours unless pressed. Feels like it wouldnt pull the skin off a custard unless the revs are maintained. Ill let you know .Thanks

 

gems is extremely simple system. It wont react to no cats like the newer ones but it will still run bad because its not seeing everything. if you clear the codes and it runs ok then its definitely the lack of catalytic converters. If it doesn't then look at your fuel trims to see what is happening. it could be the lack of backpressure causing issues with the oxygen levels.

 

Thanks for the help, turned out to be a cracked spark plug,damaged on installation of the extractors. Purring like a kitten now. I am learning along the way with this car, and enjoying it .

 

Post back and let us know what kind of mpg you are getting with the new setup. Also wonder if your knock sensors are installed / connected.