Misfire under WOT

[Kyle97-clipse]

I already have a spare set of injectors, so I might as well try them first for free. If that doesnt work I will be trying a new coil pack

 

[Rising]

I'm not as smart as these guys, but i did have a similar problem a few weeks ago. Car was missing at low rpms in the higher gears and every once in awhile at the high rpms.

Turned out to be the spark plugs... a new set of NGK BKR5E's and she was running great.

Plugs are alot cheaper than coil packs and fuel injectors. Might be worth a shot.

 

[Kyle97-clipse]

Already have new plugs, today I only did one pull and drove normal for the rest. During that pull it did not miss at all. The only thing I can see that I would have done to not make it miss is by reseting the ecu and clearing a bunch of codes, which didn't come back thank god.

 

[Fotowntalon]

hopefulyl everything is resolved. these cars can have some awkward problems like that.

 

[Kyle97-clipse]

UPDATE

Well guys the prob;em is definetely not fixed, I don't know what happened it ran great for a few days. It started missing again and you don't have to be at full throttle for it to miss anymore either. I put stock injectors back in, no difference. I think I'm going to try a new coilpack, any other suggestions???

 

[Fotowntalon]

if all the fuel components are good, then i would do a compression test. If the problem is getting worse than worse i am wondering if your head gasket is leaking, and slowly getting worse...

 

[rstchris]

Don't waste time on injectors. If the MIL is flashing during a misfire it is a hard missfire from an IGNITION problem. If a coil goes bad it will most likely stay bad and not be intermittent. I had an issue much like this on my old RS-T, it turned out to be a cracked coil negative wire in the big loom that runs over the trans to the ecu. It had some water in the loom from washing. Uncover the 3 coil wires from the coil all the way to the ecu and insulate them seperately. Also, the 420a plugs should be gapped to 044, you should regap them often as the ignition is very strong and plugs can erode fast.

 

[Kyle97-clipse]

Okay thanks rstchris I guess before I waste my money on the coilpack I'll check those wires. Fotowntalon I appreciate the advice but I did do a compression test 205 across the board.

 

[LD25Delta9]

N/A Plugs should be gapped at .38. Turbo should be gapped to .28 But I suppose everyone has their own "difinitive gap."

 

[Kyle97-clipse]

Well today I checked those three wires all seemed fine and had continuity. Missing bad all the time now, this problm just keeps getting worse. That being said I went down to the auto parts store and just ordered another MSD coilpack I'm hoping that this fixes it

 

[Fotowntalon]

to save ya some money, you might want to consider taking it to a garage, not so much for them to fix, but to put on there diagnostic tool. They tend to have way better diagnostic tools that can point you in a more specific direction, and the cost is normally under $50 (only cost me $20), in the end it can help you save more money than replacing good sensors and etc, and help ya find out if its electrical or mechanical, just another option for you if the coil pack turns out bad.

 

[LD25Delta9]

to save ya some money, you might want to consider taking it to a garage, not so much for them to fix, but to put on there diagnostic tool. They tend to have way better diagnostic tools that can point you in a more specific direction, and the cost is normally under $50 (only cost me $20), in the end it can help you save more money than replacing good sensors and etc, and help ya find out if its electrical or mechanical, just another option for you if the coil pack turns out bad.

Agreed. There's no sense in throwing parts at a car. All it will ever do is cost you money. Do me a favor though, Check your Cam position sensor. If that is worn out, your ignition timing will be all sorts of wonky. My friend has been having the same problem and after him replacing a whole bunch of stuff that needed replaced anyways, we found it to be his Cam Position Sensor. It's what tells your plugs when to fire. If it looks burnt up, replace it.
Also, switch back to some stock injectors unless you have a way of controlling them. That could be part of your problem as well.

 

[Kyle97-clipse]

Well the car finally took a dump on me Luckily I made it home because I was really close to my house but oh my god was it missing! It threw code 11 which is either the cam position sensor or crank position sensor. Cam postion sensor tested out okay however on the crank sensor there is no voltage going to it. There is not even any voltage coming out of the ecu to go to it. I think it is pretty rare that the ecu could have went but stranger things have happened I guess. Then when I fired the car up today it ran great for a few minutes, even took it for a quick spin however it started acting up really bad again. If the ecu was bad and the crank position sensor was getting no voltage I dont even think the car would run. Any ideas??? The car is going to the shop monday though

 

[RoninEclipse2G]

It could be a bad ECU or a bad wire. Double check the section of the harness where it runs right next to the EGR tube. It might have melted and is shorted or grounding out. Or perhaps the wire is damaged somewhere else.

On the bright side if it's the ECU, I've got a spare 97 ECU that you can have for cheap

 

[Kyle97-clipse]

Checked wires they all look really good I'm going to see what the shop says if they do say ecu I'll let ya know

 

[tnl]

My car used to do the same thing with the msd wires. I went and bought some megnecores from stm and they came with new plugs. Soon as I put the new wires on the problem went away. So could just be the msds

 

[Kyle97-clipse]

Update

Well the shop called today and guess what they found the problem! Bad diode in the alternator they said and are 100% sure it will fix the miss. So Im going to pick up a new alternator this weekend and tackle the job

 

[boosted97RS]

Not to dig up an old thread, but did replacing the alternator fix your problem? I seem to be experiencing the same exact thing.

 

[Kyle97-clipse]

Yes I havent had one miss since the alternator knock on wood

 

[Fotowntalon]

it suprises me that it was the alternator, last thing i would have thought of, but the most imporatnt thing is that the problem is solved!

 

[Kyle97-clipse]

Yeah it really surprised me too and I said to the shop I'm like 100% if I replace thst alternator it won't miss and there like yep, so I did and it was fixed. Lets just hope it stays that way