i have had my vn now for about 2 months (not the first one i have owned) i originally bought it to repray and lower but the rough running needs doing fist. now this is what it does: 1: idles rough in drive and reverse (while stopped)but not in park or neutral. seems to drive ok when moving. 2:has not got the get up and go these cars are known for (my ef falcon is faster??!!) which confuses me. 3:when you take off fast from stopped the car has a shudded going through the whole body. 4:has the same shudded in the body when you go faster than 70km/h but also shuddeds through the steering too. :bang: already done is: new altern, fuel pump, powersteering pump,all idler pullies, new exhaust system, new 18in alloys and tyres new brake pads and machined discs, gets serviced every 7000kms leads oil etc. (bought car from father in law so services have been done this way for 10years) ingectors serviced. CAN SOME ONE PLEASE HELP ME FIX THESE ISSUES. kind regard Naomi.
get a compression test done i expect you have a burnt valve this would explain the lack of power and the rough idle and easy way to figure out exactly wich is the problem is to rip the valve rovers off and romove the rockers and spark plugs then make an adapter to allow you to pressurise each cylinder with an air compressor throuigh the spark plug hole. if a vlave is leaking youll be able to feel air coming out the exhause (exhaust valve) or the intake (intake valve) if the cylinder doesnt hold pressure and no air comes out the exhaust or intake then check the dipstick and if air comes out there that indicates stuffed rings or if it blows coolant out the radiator or bubles then you have either a blown head gasket, cracked head or cracked cylinder bore this is by far the most comprehensive test you can do but if thats to much for you just go to a mechanic and ask for a copression test and a cooling system pressure test shouldnt cost you too much. it should definatley walk all over the ef The shuddering could be a wheel out of balance, a wheel alignment issue or the tailshaft out of balance
if you haven't already, check that the harmonic balancer is OK (on the end of the crank). sounds obvious but easy to miss.
check your plugs again and gap them. test the coil packs and dfi module. check for hard broken and cracked vacume hoses on the engine. check for error codes. rest the ecu. change fuel filter. check engine mounts. get your wheels balanced again.
i had a very similar problem, and it turned out to be the coil packs... so make sure you put that on the priority list to check out
