So, I'll try to make this as short as possible.

I was on my way to the track last weekend, did a 3&4 gear pull on the freeway then the car started missing, what seemed to be ignition breakup, I got it off the freeway and pulled into napa, opened the hood to find oil in the plug hole on #4, I figured "cool, theres the problem" fixed the plug wire hole gasket, put a new set of plugs in, still doing it. After messing with it for 2 hours in the parking lot I said screw it and jumped in my friends car and headed to the track. I come back 6 hours later and the car fires right up, runs perfect. It idled in the parking lot until it reached operating temperature, at 180f it started doing it again.

I towed the car most of the way home behind my buddies truck, got 5 min. away from my house and started it, runs fine. I ripped it home, runs amazing, spins 3rd, runs just as good as ever. Get it home let it idle in the garage for 15 min. It starts running like crap again. It runs perfect until it gets to operating temp. the only way I can explain it is it runs like a car does when its running out of gas.

I'll go over what I HAVE done.
swapped plug wires
new plugs brk7es-11 @ .020 gap
fuel pressure is fine 48psi consistant
new ignitor in the dizzy
new coolant temp sensor
new ecu
compression test = 215 over all 4 (perfect)
swapped main relays
checked resistor box wiring
It does NOT lose power to the coil or the fuel pump

The car is a stock bottom end ls/vtec right now on 110 octane @ 18psi
PTE 880cc injectors
Resistor box
ITS GT61S turbo
Motorola 2.5bar
Stock Ignition system
Dyno tuned on chrome by D. Lee

Any ideas?

Things I thought about, possibly the coil? resistor box? injectors?

I'll try to get a video up later of how this thing runs.

 

The ICM and coil are the two ignition components most prone to problems when hot. Since you're replaced the ICM, the coil's the next most likely.

 

Wait until it acts up, gently clamp off the return hose to the fuel tank and go for a short drive, this is called Dead Head Pressure, if the problem goes away, you have a fuel delivery issue, bad ground or weak fuel pump when it gets hot, how much fuel in the tank.

It does sound like a coil getting hot though???

 

Not a resistor box, I replaced it, measured resistance @ injector clip and it showed 2.7 ohms, I believe thats what it should have. Not a coil either, I also replaced that.

I'll try the return line clamp, I upgraded the wiring on the pump and wired a relay directly from the battery recently, the pump maintains power even after the car dies, and the fuel pressure gauge reads 48 psi even after it dies. There is almost 3/4 tank of gas in the car. So I don't think its a fuel delivery issue, I could be wrong though.

Here's a video of it acting up.
http://s39.photobucket.com/albums/e1...=VIDEO0033.mp4

 

Sounds like you have an exhaust leak too, I dont mean the loud exhaust, I mean the backfiring. What does your motor still have on it from a stock motor or an equivilent sport version. O2 Sensor, EGR Valve, IACV or FITV. I would be looking at these.

 

I have a exhaust leak at the vband under the oil pan, from welding the flanges without them clamped lol. I do not have an O2, PCV, FITV, EVAP, Knock, all those are turned off in chrome. I DO have IAT, IAC, I beat on the iac but I plan on replacing it once I find one.

 

So it idles fine when cold, drives fine, then once warm it will idle like crap, and you will have to keep the revs up otherwise it will stumble and die? But once you start driving it when its warm it seems pretty normal?

If that is the case i would check for a vacuum leak. I recently had this issue on my car. IT would drive great, then about ~10 min from home when i would get to a stop light, it would idle really low and stumble unless i kept the throttle open. Then i would drive off, it would drive normal till the next stop.


It's possible it could also be a clogged filter screen on the IACV. So removing that and checking the filter wouldn't be a bad idea.

 

Well clean the throttlebody and butterfly valve, remove the IACV to clean it also, dont use carb cleaner, too strong for the IACV, use brake and parts cleaner.

 

Figured I'd update this since I figured it out, I hate it when I search old threads and people don't say what the problem was.

MAP sensor was bad. Bizzare, no CEL and no irregular map values shown. Replaced it with another 3 bar and it runs amazing once again.