Vespa px150 2014 model not running smoothly and feels like it is missing especially at low speed. fitted new NGK BR7HS which seems to be the right plug.

SOURCE: not firing right on no.4

First check plug and make sure the right plug for this vehicle,make sure that the heat rating for this plug is correct. Your problem could be a wrong heat rating plug been installed. Also make sure that the misfire is due to a bad plug and NOT a bad injector or injector wiring or uneven compression or even bad coil. Check injector wiring and make sure it not shorting or broken. To check injector pulse use a NOID light can be bought at almost any auto parts store like Auto-zone etc. Also compression can be checked with compression guage. A rule of thumb to go by is if any cylinder has more than 10 PSI in difference in compression there is a problem like a burnt valv etc. Here is a n example cyl# 1 170psi cyl#2 176 psi cyl#172psi cyl# 4 150 psi, there is a problem with cylinder # 4 and will cause a miss from cylinder #4. Good luck and thank for using FIX YA

SOURCE: running roug at low idle, smooths out at 2500 rpms

change plug and wire if its been a while most cars have 90000 miles platinum plugs in them.but the wires wear before plugs.so change plugs and wires.+clean fuel injectors .change fuel filter and air filter.if car still run rough your idling to low.have idling check .

SOURCE: The Proper plugs

should be around .30-.35". You most likely have a dirty carb issue which will cause the bike to run poorly at lower RPMs as this is on a different fuel circuit in the carbs, know as the pilot jet. You may be able to run some carb cleaner through them. I recommend seafoam, or chevron techron. Mix according to the instructions on the bottle.

SOURCE: My 2003 VW Passat, 1.8 lt. The engine has a miss, runs on 3 cyl.

start with the fuel filter.

SOURCE: G'day, I have a simplicity express ride on mower that was running when I got it, I've put a new battery in it, new spark plug, new fuel filter and new fuel lines. Last time I used it was running great

that video sounded like a very low battery, and, if you know your not getting spark, check the plug wires for continuity, and that there are good connection to spark plugs, once you get spark, then make sure you are getting fuel