636Racer

iTrader: (1)

I did a search and all are pretty relative to what been happening to my car.

typical symptoms, the car shudders and hesitates from warmup - on. driving the car, it bogs and backfires at speed.

I pulled out all the coils and tested their resistance, all were pretty inconsistent but I highly doubt all the coils are bad. I didnt know what numbers I should be looking for, so I checked the plugs. Plug number two was wet, indicating no spark. So I replaced all the plugs assuming that plug was fouled. Still, no spark. So I switched the coil from #4 to #2, the car ran more terrible! and found that #2 plug was wet...So then i assumed that coil was bad. I put the coil back in #4 just so it's a little driveable just so I could drive it home from my grandparents house.

I replaced the coil yesterday and #4 is still not firing! I havent tried moving the coil this time around. So i started searching on here.

Anything else should i be checking for? where to test and what numbers to look for when i check anything with the amp/ohm meter?

Power mods on the car is: 1/2" plenum spacer, test pipes w/non-foulers, aftermarket y-pipe to a single canister exhaust with the sound baffle on. All these mods were done back in 2006, no problems up until now.

Thanks!

uzme8679

iTrader: (8)

i have the same code, but i have the leaking valve cover problem. where oil is leaking on my plugs and gives me the random misfire code. it may not be your coil packs. i would start with the least inexpensive thing. and take out all spark plugs and see if you have any oil on them. If so you may want to invest in a new valve cover and plugs to stop the p0300 code. But the valves covers are expensive high 200.00/each good luck.

636Racer

iTrader: (1)

Well, I had the driverside valve cover serviced by the dealership early last year since it had warranty at the time, no problems up to now. All of my spark plugs have been replaced.

636Racer

iTrader: (1)

Update: We've got a hold of the Consult 2 on borrowed time. Now it brings up P0037 P0304 P0037. I doubt the O2 sensors are the culprit because theyre picking up consistant voltage, probably due to the unburnt fuel from cyl.4. We're going to check the injectors next? Just waiting on the engine to cool down a bit.

636Racer

iTrader: (1)

Update:

Since then, We've replaced the coil on cyl. 4, still ran like crap. We confirmed spark with some doodad my dad has at his shop. So we came under the assumption it was the injector. we ordered a new bosche injector, upon recieving it, physically the injector looks different but it was noted that it was an updated design.

Today we replaced the injector and the car still ran like crap! I cleared all the codes, took the car on a quick drive, oddly...the CEL never came on. I ran an idle learn sequence, where i started noticing the CEL blipping on whenever there would be a misfire while taking it back out to drive again. We didnt have a Consult-II on hand so I had to count the blinks. P0304 was gone, however P0300 and P0037 were still on, however no solid CEL was on.

The thing I dont understand that the P0304 and P0037 are on opposite (exhaust) banks. But if it were at P0031 or P0032, I would understand the relation to P0304.

Going down the list of "Possible Causes" in the Service manual: (for anyone who's doing a search)

•Improper Spark Plug - Replaced all 6
•Insufficient Compression - will check
•Incorrect Fuel Pressure - will check
•The injector circuit is open or shorted - Replaced no.4 injector
•Fuel Injectors - all confirmed operating (checked with stethiscope; ticking)
•Intake air leak - confirmed no air leak, sprayed throttle body cleaner and listened for RPM
•The Ignition signal circuit is open or shorted - replaced coil
•Lack of fuel - will check
•Signal plate - not applicable (M/T)??
•Heated Oxygen Sensor 1 - will check (P0037?)
•Incorrect PCV hose connection - will check

Any addtional input from you guys would be great! until then...stay tuned.

Z_enthusiast

iTrader: (16)

I have the p0300 atm also which is random misfire. but i have a 2step and i destroyed my cats. so about to order new cats then i should be good. maybe this could help?

636Racer

iTrader: (1)

i have test pipes in place of the cats, so im in limbo as to how that goes. thats why im questioning the relation of P0037 to P0300.

Z_enthusiast

iTrader: (16)

wow... crazy, but sounds like your surrounded by the right technicians. so just keey doing what your doing and check those listed. youll work it out. keep us updated.

636Racer

iTrader: (1)

Will do; unfortunately I'll have to wait until the weekend to free up any time to look at the car again. Having a dealership tech as a Father helps. He's a Honda Tech, but Nissan is their sister store. That helps immensely, especially with getting some replacement parts.

MrGlass

OP, you ever figure this out?

636Racer

iTrader: (1)

nope, sorry. I put the car in storage and currently acquiring an LS2/T56 and Sikky parts. I had to question the overall costs since I was enroute of turboing the car. Replace parts vs. Upgrade. I'm opting for the Upgrade. Having a best friend who specializes in corvettes help me stir in that direction.