d16y7- Cylinder Missing Under Load
 

I need some ideas. Details: Always idles fine and drives good when cold for about ten seconds. After that if I throttle it more than 1/8 of the way under 4K rpms, it will act as if one of the cylinders is missing and stutter. When I get over 4k it'll smooth out and go. It's not the coil, the wires are newer ones, plugs are 1 year old and they look good. It doesn't bog when I floor it, just misses. I checked the injectors with a screwdriver and they were all clicking as normal. Any thoughts?

You cant check injectors at idle if the problem isnt at idle.

Pull all the plugs, check if one is running hotter than the other. Could be a bad injector.. or it could be a sensor parameter going out of wack. A datalogger would be nice.. but obviously you dont have one at your dispense so I would start by pulling plugs and looking if one cylinder is different than the rest.

how old is the cap and rotor. too many people forget that the cap and rotor arc just like a sparkplug and deteriorate over time since they transfer around 50,000V

If you rev the throttle at idle, the miss is apparent so that's how I checked them, but the clicking was steady and consistent with revs. Cap and rotor is about a year old but it's always a possibility. I'll swap with a spare I have here.

Swapped the cap, same thing. No spare rotor now. Will check it out later.

clean the cap and rotor lightly with some 320 grit sandpaper and try again.

does the condition happen when the car is cold? or only when warm? if cold, it kinda makes it unlikely that it's a sensor as the ECU runs open loop. it could be, but it makes it unlikely. and if it's not a sensor problem causing fueling issues, then it's again back to the distributor/ignition area.

mist the area lightly with water as the car is running and see if the condition worsens. also, being OBD2, if you have a laptop you should just get a scantool and log your ECU values. it'd be very helpful.

I had a scantool, but it was stolen a few months back:mad2:. I'm going to have to grab another one.

have u examined the plugs yet?

Haven't had a chance yet because buy the time the engine cools down, it's too late for me to do anything. Going to do that today. My OBDII port isn't working. My new scan tool doesn't power up. Anyone know of what pin is designated to what? Gnd, 12V, PCM...???

Oh, and this only happens when the car has had a chance to warm up for over ten or fifteen seconds, so it could be a sensor. And just to confuse the situation more, I passed my etest with this problem- probably because he didn't load the engine, just cruised gently up to 2500.

Okay, I got the scantool working and found seven codes! HA!
1- MAP Circuit High Input
2- IAT Sensor 1 High Input
3- 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
4- Cyl. 1 Misfire
5- Cyl. 2 Misfire
6- Cyl. 3 Misfire
7- P1300- Whatever the hell that is...

Time to check connections and then get a few sensors...

just grab a test light and check all the fuses with the key on. You'll find a blown fuse, then replace it. Should power right up

lol.. well theres your answers

Oh, it was a bad plug that was arcing to the block. The trouble codes were from when I was checking to make sure the connections were alright. After I remembered that and clearing the codes the only code was Misfire #1 Cyl. Don't buy Bosch plugs, stick with NGK.