Serious misfire on idle and while driving


New Member
After having a few coolant leak/overheating issues (from split hose) the past week and fixing it all and did a full coolant system flush the car is now running like complete shit.
On idle it misfires quite aggressively and while driving its not much better. The only other things I tampered with recently was fitting a slightly larger cone filter (required me to unplug the MAF to get it out and fit new reducer part for cone) and the vacuum set up.
With the vacuum's all I did was replace the overly long/worn out hoses with better newer ones and there was one that wasn't even plumbed into anything but I followed the diagram on here and set it all back up.
It had the plugs and oil changed a month or so ago but will be doing it again soon for winter.
Also considering giving it a compression test later to rule out anything else.
Just did a fault code check and came up with 55 (so nothing).
I'm out of idea's it ran fine when bleeding out the system it was only after I changed the vacuums and unplugged (then pugged back in) the MAF.
Any help appreciated!

The Doc

Staff member
Check the rotor arm in the distributor is not loose as the bolt holding it in can fall out, check the dizzy cap,check plugs and also check that the plug wells have not filled with water in the cylinder head.