Johnnyb46

Soon *** I start my car in the morning my check engine light flashes so I will have to turn offf my car and the flashing check engine light will stop I get codes p0300 p0302 p0304 p0303 & sometimes p0301 that’s all the spark plugs on the right passenger side the left side is fine I did new Oem spark plugs and coil packs even switch coils to see if they was bad but no change wat so Ever my car is straight piped with a X pipe installed it wasn’t doing this at first I dnt knw wat it can be any answers to this

BlackML550

Any other codes in last few months? Id be checking for vacuum leaks. start with checking battery and alternator health and then vacuum leaks. My M273 did this once because I hadnt put the airbox on fully. When cold, spray some brake cleaner around manifold mating surface with head given they all happen on one side. Be careful not to start a fire. If revs increase then you know. Check for damage to headers as well. Did you keep the cats and sensors? Maÿbe exhaust on one side is restricted- H pipe causing too much back pressure?

Johnnyb46

air box is on right car does not rev just misfire wen you first start it and no cat or sensors are on the car it drives good wants the car is warmed up but misfires when u first start it but only the passenger side no other codes but them come up

BlackML550

When were the cats and O2 sensors removed? At the same time as the H pipe or beforehand? If the cats went before and it was fine then its probably back pressure from the H pipe. If not, the ECU is looking for signals from the O2 sensors as its in closed loop whilst the cats are cold. When the cats warm up, the rpms drop. Since there's no 02 sensors the ECU is confused?

Johnnyb46

yes I did eve everything at once cut the cats off and resonators and mufflers but everything was fine till bout a a couple months then it start doing that and I have a X pipe not H if I installed o2 sensors even tho I dnt have cats will it work or I shud get a tune for this

BlackML550

I'm sure they'll be views from others that will give you a more definitive opinion. Problem you have is because of the changes, you can't be certain that it's the O2 sensors or something else. I'd find a reputable tuner to advise you on the removal of the O2 sensors and cats.

I'm struggling to work out how the ECU ooperates things like fuel trim and the adjustments its meant to make without the O2 sensors. What does your scan tool tell you about fuel trims? Should be less than +/-8%. Has fuel economy changed?

Alans55S211

With no 02 sensor I would expect you are running too rich.

Johnnyb46

so you sayin I need a tune since I’m running with no cats right or I need to install some 02 Sensors

BlackML550

Was thinking about your problem again. In addition to what's already been raised, and since all your misfires come on 1 bank, its possible that your cam timing is out, but just on 1 side. Does it do it all the time, or just when cold?

Were there any other codes and I'm not referring to OBD codes but module by module scanning codes? Might be worth considering the camshaft and crank sensors of the problem is persistent.

Johnnyb46

it do it when it’s cold and sometimes if I’m driving the car will start to misfire and check engine light will flash I’ll pull over and cut the car off and back on it will go away someone els told me to check the spark plugs to see if oil was on them when I took them out no oil on the side spark plugs look dry he said that side bank might be getting to much gas and no other codes I might have to go get it hook up to a star tool to see other codes