An issue arose earlier this week when going to pass someone. The car starts, idles, and runs fine up until around 4500-5500rpm's, as soon as I hit that point it will sputter and lose considerable power. I changed my plugs, cleaned both MAFS, and my air filters. I have a full megan exhaust, test pipes, and fujita intake. I checked the codes and only one popped up, the downstream o2 sensor which I was already aware was blown. Any ideas? It's a 2007 base model.

 

I forgot to mention, i've been searching the forms all week for solutions and couldn't find a thing. Also, I'm going to make a video of the issue and post it as well.

 

Are you tuned? Could be a lean misfire. Mileage on the car?

 

untuned :/ it just seems odd that the problem would arise now. Its had the bolt ons since around 20k miles and I just broke 50k miles. It does seem to lean out a touch though according to my air/fuel ratio gauge when the sputtering occurs. I'm going to check out my fuel filter.

 

Nevermind. just did a quick search and found out it's probably not that.

 

I had a car that did exactly that a long time ago. No one at the dealership could figure it out. An older tech swapped out the spark plug wires and it fixed it. Maybe check ignition wires or coil packs on the VQ. Is it throwing a code?

Ninja edit: The other techs checked the resistance on the wires which checked fine. The older tech said they will measure ok until they are in use and heat up.

 

the only code it's throwing is p0057, which is a down stream o2 sensor that i knew was blown because i did the nonfouler trick. when i pulled the plugs they all seemed spot on, wouldn't a bad coil or wire foul up a plug or show on the plug at least? i just don't want too go and drop $200+ on all new coils or wires if its not the issue. has anyone had any experience with bad gas? could it be as simple as that?

 

Running 30k miles with those mods untuned is a very bad idea. Some Hr's run ok some run super lean with mods untuned.

 

That's what I'm beginning to think. I ran fuel treatment through it and it made a slight improvement, but overall the car is still running like butt. I'm going to get it on a computer and recreate the issue and see if we can find anything, but other than that my next step is just going to be an osiris uprev tune. Does anyone have any suggestions on tune shops in southwest florida?

 

I think I've found the problem. Cylinder 1 misfired today and I think the sputtering issue was just that particular coil starting to go and today it finally went. Now, what brand coil should I go with to match the other stock 5?

 

a Niss. stock one

 

Update on the situation, I replaced the coil in cylinder 1 and the issue subsided for about 55 miles then came back. Threw the code p0301, which is a misfire in cylinder 1. I have noticed that when the misfire is occurring my air/fuel ratio drops wayyyyy lean. The only thing I can think of to do is now replace the injector in cylinder one. Any input would be greatly appreciated. Thanks.

 

New update, I found a spot on injector 1 where the previous owner had spliced into the plug for injector 1 for the stupid viper remote system it had. Over time it completely severed the wire so i stripped the wire and used a solid splice to reconnect the wire. the car will run and idle solid until I really drive it, aka do a launch or take it to redline, then it will just steady misfire. any ideas guys? attached is a picture of how the previous owner had spliced into it.

 

here's is how i fixed it. I feel as though its not a good enough connection. What do you guys think?

 

Should probably solder that wire connection, the injector and coil controls are quite sensitive to changes in resistance and it could be causing an issue at very high PW (full throttle) which is causing the injector to shut down. Or that injector could be mechanically faulty from all the time running without constant power signal/strength. I would repair the wire properly, and replace that injector, if it was my car.

 

Things i've done; changed the plugs (all 6), replaced the coil in cylinder 1, switched the new coil in cylinder 1 and 2, fixed injector connection, pulled the plug in cylinder 1 and it has solid spark and burn (not fouled or lean). The misfire in cylinder 1 still persist. It seems to kick in when the car reaches operating temps. could it be a valve sticking open once it gets hot? Would that make sense? My buddy is bringing over a noid light to make sure the injector is copacetic. any other suggestions? I would really appreciate any help anyone could give me. Thanks.

 

I'm probably gonna do so once we get a noid light on it and see if the injector is indeed the issue.

 

Problem seems to have been solved and i couldn't be more embarrassed about what it was. I was missing the rubber gasket on the oil fill cap....it was a vacuum leak -_- don't flame me please. Just so everyone knows, if you have an issue that seems anything like mine check that cap.

 

Glad you solved the problem. Thanks for updating the thread. No reason to be embarrassed. I would have never made that connection.


How did you figure that out? That's completely fascinating!

 

Don't be embarrassed. Still that injector wiring issues was definitely something that needed to be fixed.