Blk99ek

The car is a 1997 camaro 6 speed
3 weeks ago i ran my car at the track and sprayed the nitrous, it was detonating but not horrible bad. Come to find out my stand alone fuel pump was only putting out 7 pounds of fuel pressure. I drove the car after figuring out why it was detonating when the nitrous was sprayed but never sprayed it again because i haven't replace my stand alone pump. Last week the car started acting up, it runs great when its cold but once it warms up it starts missing and cutting out from 1000-3500 rpms and shacks the car really bad. I hooked a big computer up to it and watched all 8 cylinders while driving it and it never picks up a missfire, then i watched the timing and at idle it sits around 22-24 degrees and when it starts missing it drops to 16 then once i get passed 3000-3500 rpms the car pulls great and timing jumps up to 29 degrees and higher. Please help i've replaced 02's and icm and plugs. Car is not throwing any codes what so ever.

Thanks David

jaycenk

iTrader: (1)

fuel pressure regulator? are you sure it's the pump?

Blk99ek

I apologize i didn't put that in there, yes fuel pressure is perfect even when it starts to hesitate and shake the car and miss

davorocks

icm? checked it?

Blk99ek

Yes put a new icm on and still the same results

nitrous2fast

iTrader: (2)

do you have headers?

Blk99ek

Yes I have headers and all the plug wire are fine and it has new plugs, oil smelled like fuel and come to find out the adjuster screw fell out of my fpr so I put a new screw in it and set the fuel pressure amd car still runs like ***

jaycenk

iTrader: (1)

Plugs fouled? New plugs before or after the reset of FP?

projektnitemare13

iTrader: (4)

One thing that can cause it too, once the engine warms up it goes from open loop to closed loop 02 sensor. If the sensors are alittle slow or arent working quite right, they can cause really rough running or stalling.

pro94lt

you need to verify if its running bad in closed,open loop or both. if its only runnning bad in closed loop theirs a good chance your 02's are lazy as stated. did you happen to use bosch? I had a similar problem that haunted me for months it turned out to be "lazy 02's" or so i think. Did you have a backfire? It would be a long shot but it could have torn your intake elbow as they seem to get brittle also check for any opening from your maf to your tb a tear or leak WILL cause it to run bad in closed loop since the 02's are giving feedback while they are not while in open loop.

nitrous2fast

iTrader: (2)

How about the o2 sensor wires? they tend to get a little close to the header and melt together... check them first to see if you o2's aren't giving you trouble.

SS RRR

iTrader: (2)

Unplug your O2's and see what happens.

Blk99ek

I'll put the computer back on it and keep my eye on open and closed loop and I'll check my maf. I unplugged the 02's and still ran horrible after warming up.

Blk99ek

Plugs were replaced after adjusting fuel pressure was set

Blk99ek

Bump anyone???

pro94lt

codes? which o2's did you unhook? I'm not sure on a obd2 if it forces it in open loop if you only unhook 1 sensor.

96TransAmboosted

iTrader: (8)

I would think that if the o2 sensor wires were melted together that would set a DTC. If yu still have the TECH 2 or MODIS you were using to watch the data then i would think you were looking at your o2 while doing your DIAG correct? if not i would do it all again from a COLD start untill CLOSED loop, then a 5mile or more TEST drive. And while on the TEST and you feel the car bogging or missing save that file and review later. Watch the MAF,o2, and fuel trim and go from there. sounds like you have already started testing the fuel and spark already. The miss fire counter stay at 0 for all cylinders the entire run? you changed your plugs since you sprayed it?