Loss of HP and misfire

[PhilipMc]

I have a 98 eclipse gs automatic 420a. I have been misfiring and have had a loss of hp and cant seem to figure it out. I changed the coil pack the wires and the spark plugs. My egr valve is disconnected, and I just fixed the slight exhaust leak I had. I think it might be a colapsed muffler because im not getting any cels besides random cylinder misfire and misfire cylinders 1-4. Any thoughts?

 

[xcasbonx]

Did you properly gap the plugs? Stock specs are around .048 - .050

I'm throwing this one out there, but possible bad gas or a dirty injector as well.

 

[starfish]

Def change fuel filter.Ive had water in my tank from gas station before.They sold me $30 worth of water.\.It worked out good for me.Their inssurance sent me a check for $861 for replacing all fuel components and computer.They still never paid me the $30!

 

[PhilipMc]

I changed the fuel filter and the plugs are supposed to be .35

I dont honestly know about the gap I was told .35 but ive read everything from .36 - .51 as the gaps.

 

[8BoltDSM]

check your owners manual for the recommended plug gap. also sparkplugs.com is a good reference i have always set mine to .044 but .039-.045 is recommended sounds like bad gas or similar issue if it is throwing random misfire codes

 

[TheRock0720]

I had this same exact problem last January with my 99 RS. I ended up replacing the coil pack, spark plugs and then the spark plug wires. That worked for about...5 days then I starting misfiring again. So I replaced the coil pack and spark plugs with ones from the dealer and boom, over a year later and she's running strong (except for the head gasket oil leak, but that's getting addressed as we speak).

The reason why I'm so confident in this solution is because I've seen it many times on this forum and I've personally had it happen to me a few times (this misfiring on cylinders 1 and 4).

The left side of the coil pack is for cylinders 1 and 4 and then other side is for 2 and 3. So usually when you see a misfiring happen with a whole set, it points to a coil pack and/or plugs and wires.

 

[PhilipMc]

Thanks guys and I have one more question. If you have iridium plugs do you have to gap them more than .35 cause they told me its supposed to be .35 at auto-zone but all I have seen is people saying .39 - .50 but they never specified if they were iridium.

 

[TheRock0720]

Thanks guys and I have one more question. If you have iridium plugs do you have to gap them more than .35 cause they told me its supposed to be .35 at auto-zone but all I have seen is people saying .39 - .50 but they never specified if they were iridium.

There's no need to be running iridium in our cars (420a's). Champion RC9YC5 (OEM plugs that came with the car right out of the factory floor) or NGK BKR-6 (gaped to about 0.045ish).

Original document from the manual:
http://www.dsmtuners.com/forums/attachment.php?attachmentid=120188&d=1300040674

 

[PhilipMc]

Why is iridium bad? and can you gap iridium plugs?

 

[95TalonOwner]

You will damage iridium plugs by trying to gap them. Get NGK BKR6E gapped at .045

 

[PhilipMc]

Aren't iridium plugs better?

 

[95TalonOwner]

Basic NGK's have been proven over over and over again with our cars whether it be a 420a or a 4g63. Iridium is a waste of money for us.

 

[PhilipMc]

But by basic ngk do you mean copper? Because I heard copper plugs are garbage.

And will the iridium plugs still work or could that be whats causing my misfiring?

 

[95TalonOwner]

Yes copper. BKR6E are copper plugs and are best for a stock motor.

 

[94allwheeldsm]

I have tried almost all the plugs that fit our cars and none have come close the the NGK i can tell the difference between them and others. I have been recently trying the E3's and they are proving to be a good plug i might just keep them in.

 

[PhilipMc]

Yea i have NGK's but they are iridium and I just gapped them to .40 so I hope that helps. I think that the source of my problems is my egr valve, because I disconnected the vacuum lines going to it but I didn't remove it.

 

[Calan]

Yea i have NGK's but they are iridium and I just gapped them to .40 so I hope that helps. I think that the source of my problems is my egr valve, because I disconnected the vacuum lines going to it but I didn't remove it.

Gapping your plugs to almost 1/2 inch is most likely the problem.

 

[PhilipMc]

sorry what I ment to say was .040"

 

[97 EclipseRS-T]

Check to make sure your harness on the right side of the motor (with coil connecter) isn't melted or have any bare wires. Same thing happened to me once replaced everything i could think of, then saw that my harness was melted.
Good luck.

 

[PhilipMc]

Check to make sure your harness on the right side of the motor (with coil connecter) isn't melted or have any bare wires. Same thing happened to me once replaced everything i could think of, then saw that my harness was melted.
Good luck.

I did what you said and unfortunalty it wasnt it. I think it might be my throttle body position sensor now. Im just gonna change the cat and all the sensors in my car.

 

[glennsanity]

i was having the same problem just last night, i was driving around 70-80mph then the CEL came on then i felt the my car lost hp.. My plugs are new so are the wires.. someone told me to try replacing the coil packs. Hopefully that will end my problem.

 

[95TalonOwner]

i was having the same problem just last night, i was driving around 70-80mph then the CEL came on then i felt the my car lost hp.. My plugs are new so are the wires.. someone told me to try replacing the coil packs. Hopefully that will end my problem.

Check your egr valve.