GU rough idle

[MNBS 4x4]

I have a '99 4.5GU auto wagon and it is starting to feel a bit lumpy when idling,I have been told the tappets may need adjusting. I know my GQ had adjustable tappets, does the GU have the same and could this be causing the rough idle if not set properly, also is it a big job (expensive) to set them up properly. The car drives smoothly but just when you come to traffic lights etc, it does it in drive or neutral when stationary.

Sorry hope this makes some kind of sense to someone.

Regards

mnbs 4x4

[GUtripper]

I'd suggest before tappets you look for a air/vaccum leak. Check all hoses to/from manifold and injection system.

Then have a look at spark plugs/leads/coil packs.

If it was tappets (unless they were waaaaay out) it would just tick a bit at idle.

[swb_ute]

Just had the same thing happen to my 4.5L replaced the plugs and leads and it made a huge change.

[jessie928]

do a compression test.

i have a 4.5 motor pulled apart as we speak, same issue, was down on one cylinder.

Jes

[MNBS 4x4]

do a compression test.

i have a 4.5 motor pulled apart as we speak, same issue, was down on one cylinder.

Jes

any idea what the costs involved are for your repair

[jessie928]

do a compression test.

i have a 4.5 motor pulled apart as we speak, same issue, was down on one cylinder.

Jes

any idea what the costs involved are for your repair

hi man,
its not my truck, im doing it for a mate

hopefully yours is just a headgasket or a burntt valve (something simple!)

quality vrs kit 180
OEM bigends 80
OEM piston rings 380

you can actually oversize the block and install aftermarket pistons with new rings for cheaper price than just the OEM piston rings, but we voted quick job rather than pull the engine from vehicle.

thats all it will cost him, (except packing the cone on the Hookah with double apple for the next 6 months )

Jes