piga

i havea 2000 jeep grand cherokee 4.0 with the check engine light on. the codes are p3000,p3001,p3003,p3004 and sometimes when im on the road the check engine light starts flashing and the engine doesnt respond well and starts shaking. i changed the oil and spark plugs last weekend and the coil rail about 6 months ago. i also changed the engine switch and the crank position sensor and the one that goes on top of the oil pump. i dont know what else can i do to fix this. does someone know what can be wrong?

tjwalker

With the PO300 (random misfire) along with specific cylinder misfires, you likely have one "common" problem.

I didn't see any mention of you checking fuel pressure and that is absolutely job #1. With a 2000 4.0 engine, you should have 49 psi, plus or minus 5 psi.

I will tell you this. A flashing check engine light indicates a serious misfire, which if not resolved quickly, will trash your catalytic converter. So I would recommend not driving it; resolving immediately is very important. If you need to get it into a shop to determine root cause....do so.

dave1123

Yes, I back this up. A flashing check engine light shows a serious problem occurring at that moment! It's designed to get your attention to do something to not cause serious damage, be that get off the throttle or shut it down, whatever it takes.