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p0300 miss

nicks98gtp

nicks98gtp

New member
Well Im kinda stuck, Today I sprayed off the salt on my car and under the hood to get all the crap off of it, and after I started having a pretty decent miss. The same happened over the summer after spraying the motor off but went away after a few hours in the sun with the hood open.My dilema is now that the snow and cold weather is finally here in Michigan what should I be looking at to blow out and dry off? Ive wiped down all the coil packs, blew air on the injector harness, and plugs and it seems a little better but its still there. With the cold weather and snow now I cant see it drying out on its own. any suggestions?
 


Vac Leak, Plugs, Wires, Coils, ICM, Fuel Filter, Fuel Pump, Clogged Injectors.

Those are going to be the most common causes of random misfires. My guess in your case is a vac leak from a bad gasket.
 
possibility i guess, but nothing was present before i sprayed the hood off and some of the water sprayed on the motor. Its almost like it comes and goes, when i first got done it would miss at low rpm and go away at high rpm and heavy throttle, now after about 5 hours it seems to be okay until about 1/2-3/4 throttle and the miss comes in again
 
Get a can of maf cleaner or starter fluid. Turn the car on and let it idle. Pop the hood and spray your fluid of choice at the supercharger and lim gaskets as well at the vacuum tubing. If the idle changes at any point, you have found your vac leak. If you spay all around and get nothing, your gaskets are good and we can look into some of the other options.
 
ill check it out tommorow, hopefully it warms up a little lol. but im gonna leave it in the garage overnight with heat on and unplug the sensors and throw a fan on it and hope it drys it the rest of the way out and it'll fix itself.
 
well i looked at it a little bit this morning, took it to work out and it was fine until it warmed up then it started to miss again under medium/heavy acceleration. Brought it back home unplugged all injector connectors, plugs wires, etc and sprayed them down with wd40 and blew them out with my bloe gun and wiped them dry. After i let the fan bloe on high on the motor for about 45 minutes i hooked it all back up and took it for a drive. The miss isnt present when revved in park or neutral, but when in gear cruising down the road it will show up in high rpms. Under light acceleration it isnt there but as soon as i get in it hard and it climbs upwards or 4500 rpm CEL starts flashing and it feels like its choking out, but it isnt every single time, about every other time it will do this. im thinking bad coils possibly?
 


WD40 is NOT an electrical component cleaner!

If you think it's coils, go for it. I would scan it again and see if any new codes are present.
 
well i through the little scanner on before this drive again, it should cyl. 3 misfire, and TPS circut A voltage low. cleared the codes and ran it down the street a couple times and miss is there but the light wouldnt come back on. It almost feels as though its hitting a governer at 5k rpms. I did check the cyl. 3 injector though and it had a resistance of 12.9 ohms. the others in the rail were fairly close so Im thinking theyre ok, but I also checked the 6 spare injectors I have laying around and all six of those are reading 11.2 ohms exactly. Only problem is I cant find a spec of what the injectors are suppose to be
 
Explicit_Spade said:
WD40 is NOT an electrical component cleaner!

If you think it's coils, go for it. I would scan it again and see if any new codes are present.
Click to expand...

as your right wd-40's not a cleaner, but it s a water replant, wd stands for water displacement, 40 th attempt at the formula.

i have used wd-40 a bunch of time to get cars that got stuck in floods started again, spray down the wires, plugs and distributor or coils and they all ways start up.
 
well i pulled the fuel rail and im getting readings of anywhere from 11.9 ohms to 13.5 ohms on the injectors. not sure why since they all went in at the same time, but after measuring the spares, each one of those are all within 11.2-11.3 ohms. im gonna throw those in adn wipe down the icm while its out adn see if that helps at all
 


just finished up changing the fuel rail/injectors, and cleaning off the ICM (had a little corrosion on it) and threw on a set of new plug wires. I still have the miss, it almost feels like its hitting a limiter at 4500 rpm, then when i let off and stomp it again it goes away for a few seconds and comes back. I took a video sorry for the quality, it came off my phone. But you can see it in the tach at 4k before i let off and get back in it, and right before ~5600 rpm when it does it again and i let off and get back on when it shifts into third. Now im thinking trans. related or possibly plugged cat?

VIDEO0009.mp4 video by nick_hinton1 - Photobucket
 
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