So I just about had it with this car and it's many issues , I can't seem to figure out what's causing my problem, check engine light is on and it's throwing a p0300 which is a random misfire and also throwing a p1800 which is for the vias, so far I've replaced all spark plugs, coils, checked for vacuum leaks , changed all the vacuum hoses , replaced both valve covers , did the 2k1 maf swap, and I'm just aggravated and running out of ideas , could be fuel pump related ? Car will be idling and then rpms dip low and engine light starts flashing, it also studders on acceleration and feels like it's struggling to catch speed , problem has been getting worse these past couple days , and the weird thing is it comes and goes , it seems to be intermitent, did ecu reset couple times , power comes back and it feels like a brand new car but after a couple days it runs like crap again , it's running like I have a 4 cylinder under the hood , any suggestions would be greatly appreciated, car has 140k atm and it's 6 speed , I can say I have a love hate relationship with this car right now I just want to be able to feel the vq35de glory again ...

 

Check your ground distribution and continuity. Obviously, you need to check it when the car is misbehaving.

 

Engine light flashing is bad TWC.

Basically its saying you have unburned fuel passing into the catalytic converter and theres a melt down.

Do you have a puff of whit smoke at start up?

When you pull the plugs do some appear wet?

You may need a few new injectors.

 

It did it to me a couple times when I first bought mine. Checked the plugs and some were 3 times the recommended gap. All 6 were at least double. Switched them out bam. Brand new engine. So if you did plugs and it's random, some type of timing issue.