does anybody know why my vauxhall omega 3.0 elite 1996 is backfiring threw the inlet manifold and wont rev?

Question

THIS ONLY HAPPENS WHEN ITS WARMED UP.IT WONT REV ABOVE 2500RPM AND BACKFIRES THROUGH THE INLET MANIFOLD.IVE CHECKED THE EXHAUST FOR BLOCKAGE ,IVE ALSO CHECKED VARIOUS SENSORS E.G.(CTS /THROTTLE BODY/ AIR TEMP)BY PUTTING A RESISTER IN PLACE OF THE SENSOR TO GIVE THE IT A (COLD ENGINE READING BUT TO NO AVAIL IS THERE SOMETHING THAT I AM NOT CHECKING OR DOING THAT COULD FIX OR AT LEAST PINPOINT THE FAULT/S.?? I HAVE PUT NEW PLUGS AND LEADS ON THE CAR ABOUT 6 MONTHS AGO AND REPLACED THE GEARBOX OIL AT THE SAME TIME/BECAUSE THERE WAS SOMETHING WRONG WITH THE BOX IT KEPT COMING UP ON THE DISPLAY "AUTOMATIC GEARBOX" AND GOING INTO LIMP HOME MODE. I DONT KNOW IF THIS HAS ANY BEARING BUT I THOUGHT IT WAS WORTH MENTIONING.THANKS IN ADVANCE

Answer 1

Hi

There is a slim chance that the timing has jumped a tooth or two as the folks have said.

This also sounds as though you may have a faulty O2 sensor. I believe you have a V6 engined vehicle, in which case, disconnect the O2 sensor at each bank one at a time and see if it evens things out.

If not, come back and we'll have another go.

Cheers

Geordie

Answer 2

Sounds like the timing is out but why it should happen is not so clear. Have you done any work on the engine? Maybe cam belt has slipped due to being worn out or tooth missing.
In any case the car needs help and NOT driving until the problem is fixed is best option to save you money in the longer term

Answer 3

check your timing or if it has one it may be the map sensor this sensor automatically adjusts the timing when the engine warms up or cools down

Answer 4

i own a repair shop,and it sounds like it might have jumped a few notches out of time on the belt,that will cause this to happen,id have it checked,just one notch will make it run bad two notches will make it back fire and not have any power,and this will cause it to burn a valve on the engine also,so you might want to have this checked as soon as possible ,good luck i hope this helps.

Answer 5

could it be the ecu having a tantrum due to a faulty ign amp module and or faulty coil/coil packs? i'm not familiar with this particular vehicle. is it a V6 isu lump?