420A Rough Idle on 2gNT Eclipse.

[isantop]

Bought a 97 Eclipse N/T about last June (It was right before Fathers' Day). It's loping pretty heavily on Idle. Once the RPM's get above around 1200-1500, it's perfectly smooth, and the engine feels plenty powerful. It's just below that that it's rough.

In August, I drove it up to my grandparents and we did Plugs, timing belt, head gasket, etc. I also took it into the dealer and had them check for vacuum leaks (they replaced a hose). At the time, the computer was throwing P0455 (Large EVAP leak), which is usually a gas cap, so I got a brand new, OEM gas cap as well. That just about sums up the work I've done on it on the fuel system/engine.

It shouldn't be related, but I've also bought new tires, and did the front brakes.

The computer is still throwing the P0455, and a Misfire now (which I expect with the loping).

I've got a new EGR valve coming. We took the old one off when we did the head gasket, and the EGR valve gasket was completely blocking the valve! I'm gonna swap that out and see how well that fixes it.

Anybody have any ideas where to check if that doesn't work though? The buddy I bought it off did the Coil pack/wires a little before I bought it, so it likely isn't those. And we did the plugs last year. That's my knowledge of misfires.

 

[wrencher]

Would help to have the misfire code if it's pointing to a specific cylinder.
Then you can focus your efforts on that cylinder.
Unless it's a P0300 that is a multiple cylinder misfire code.

Checked the compressions?
The plugs & or wires can still have an issue, I never assume new/newer to be good.

 

[jofe4]

does it have a 2gMAF or did some one put a GM MAF on it?

 

[isantop]

Last time I had check it was a P0301 for Cyl. 1. I swapped the wire out for the one on cyl. 2. I will say, though, that the #2 post on the coil pack was extremely dull, and unlike the #1 post. Seems odd that #2 would be in bad shape, since it was #1 missing.

I'll also check the MAF too.

On a side note, how on earth do you get to the reverse light switch on the tranny? It's the 420A (obviously), with a 5-speed.

EDIT: So, the previous owner has a K&N filter, and I can't find the MAF on it. My intake has, in order: K&N filter, tube, Throttle body. Where is the MAF located on a 420A?

 

[PhilipMc]

Try changing your throttle position sensor.

 

[dsm'r sk1mp]

Try changing your throttle position sensor.

In in what way will replacing that help his situation?????

If your running misfire start with compression. Test ask cylinders so you know the difference in each. Then check spark, continue to the plugs then to the the coils.check your injector pulse and cas. This should be your first attempt at finding the misfire.

Seeing as you are weak in two and your missing in one I would replace the coils but double check first. Leak down test would be another thing to try.

 

[admgst99]

check your power transistor too

 

[SpiderGST]

does it have a 2gMAF or did some one put a GM MAF on it?

He is N/A guys, he doesn't have a MAF. It's all in his throttle body.

Are you 5 speed or auto that will change with the reverse switch question?

When I owned a 2gNT I had to replace my coil pack multiple times even my MSD one took a shit on me. His power transistor is also packed into his coil pack that I know of anyways. I would do tbd stuff that is free before purchasing anything at all.

Follow sk1mp post and then go from there.

 

[rb26alpha]

pull the spark plugs out and see what they look like

 

[satatchi]

Im also having a low idle i replaced plugs coil pack iac sensor and all the same problem it even seems like im stroked out when idling