Hi all.
Posting this up, been searching for a bit and havent really found anything relevant.

Long story short, when I 'poke' my throttle at idle, the engine RPM decreases by 100-200 RPM before raising. Has anyone had this trouble before? My other wagon doesnt have this problem. Could it have something to do with a dirty throttle body or something similar to that? Engine is completely stock, TJ II Sports.

Also, I get a slight knock when I radically accelerate the RPM (i.e. rev) at the start, are the chances that this is an engine mount or something else?

Any help appreciated... the problems have eased on over a couple of months and the car still runs fine.

knock could be dry cams or lifters?

Money's on a vacuum leak

Edit - Your diagnosis with the knock sounds plausible. Is it the same with engine cold & hot? Can you replicate the knock with a quick flick, left & right, while driving?

The knock happens hot and cold yeah, havent really tested for a quick flick, will do soon.

Mine is the same but comes and goes.

EDIT: I am going to clean throttle look for leaks etc in the next couple of days.

does it drop revs when cold and hot? or just cold?

if only cold, its possible that your oxygen sensor is on the way out (check for vac leaks and clean tb etc first)

oxygen sensor failure may be the cause of the knock as well, in the form of detonation, although not likely in a stock na magna.

does it drop revs when cold and hot? or just cold?

if only cold, its possible that your oxygen sensor is on the way out (check for vac leaks and clean tb etc first)

oxygen sensor failure may be the cause of the knock as well, in the form of detonation, although not likely in a stock na magna.

Happens when the car is warm aswell.
Both the knock and slump in RPM happen at all temperatures. So I should clean the TB first then check for vac leaks?

yes, that is where i would start, followed by an ecu reset

Would it be worth replacing rocker cover seals?