when you press down on the gas does your rpm's go up also? or do they just stay at a constant number until the gas pedal is halfway?

The rpms go up slowly, and the car accelerates slowly. The trans isn't slipping.

Replace the spark plugs and see what the old sparks plugs tell you is there any other codes .

Okay I'll try that. There is a misfire code, but I'm assuming that's because of the rich condition.

see if this helps when you take the old spark plugs off
Verrill: Plug Color Chart

is maintnace up to date? if its not i would do a complete tune up.and keep some 93 octane

I'm having a similar problem with my 97 Eclipse GSX turbo. I changed the internal transmission filter and replaced the fluid, and it accelerates a little better now, but still a little sluggish. I haven't had a chance to check the plugs yet, but the car has had a tune up recently (aside from the transmission fluid being replaced) A buddy of mine said it might be a compression issue. Any thoughts?

You should really start your own thread, mainly because this is a 420a thread. Regardless, checking comp is never a bad idea and easy to do. If you are also running rich like the OP check your 02 sensors

from what i read, sounds like you have a massive vacuum leak. If the the codes are running rich condition, it means the ecu is compensating for extra air going into the engine. what are the exact "P" codes your getting?

hey man i got a sloww acceleration on my gs and its auto i cant even burn ruber thats how slow the accel. is i have cleand my cat and got a new fuel filter the fuel filter made it a liil faster im ganna try to change my wires and spark plugs and coil see if it goes faster ? idk and i havent done a compresion check maybe my injectors clogd or wires are messd up?

im pretty much having the same issue but when i press the pedal all the way down the rpms go up but i get very little response...any idea?

Did u try cleaning the throttle body i know it sounds stupid but i had a similar problem on my fiero and it fixed it

95eclispe said:

im pretty much having the same issue but when i press the pedal all the way down the rpms go up but i get very little response...any idea?

Click to expand...

Seems like your shit is slipping. Check fluid if your auto, or suspect the clutch if your 5 speed.

It is possible that you have a vacuum leak somewhere. If not, check out your plugs. Always start with the least expensive solutions. Good luck

I just replaced my plugs and wires all NGKs on my GS Spyder auto N/A. No transmission slippage, just slow, sluggish acceleration at cold starts and initial first driving/warm up...its as if it has to warm up then operate correctly. Are all Eclipse this way? Almost like it has to build up vacuum or something...i dunno. Trans flush is next...will keep updates

1. Spark Plugs
2. Coilpacks
3. Timing
4. TPS
5. Clogged Cat
6. Clogged Air Filter

Id try those first.

Dont run it with a misfire i ran my 2g with 1 for a whole 1 day easy driving and tryed plugs wires didnt help and then after it was knocking it was coil packs check them for corossion that way my problem but get it figured out before you have bigger problems

Okay so I literally just made my account 5 minutes ago due to an arising problem with my mitsubishi eclipse gs. Its a 96. 5 speed. 420a motor with approx 166k miles. I have been having problems with my clipse being really slow. Ita all the time. Everytime I drive it it will be slow throught all the rpms. Gets a little better at 3k but not much. I went through a full tank of gas in 4 days and drove it about 15 miles. No lie no exaggeration. It backfires like crazy and has a wierd idle. Never dies but is a really rough idle.

I have replaced

O2 sensor upstream*
Idle air control valve
cat
air filter
Plugs
wires
coil pack
egr valve
battery
oil

If you used a tank of gas in 15 miles there has to be a massive whole in your fuel system. Like burning fireball hole. It shouldn't be hard to find.

Im mean I have terrible fuel economy

What is that? 1 gallon per mile? That's motor home territory. I'm sure its not that bad.

I just have to give my 2 cents; Did you change your fuel filter? Also, to all my fellow 420a guys, do you realize that NGKs are recommended for 4g63 engines, and Champion copper plugs are recommended for 420a engines? I swapped the NGK iridiums from the previous owner for Champion copper and noticed a big difference. However, all 3 420a that I've owned all accelerate the same way; it's just how they are, I believe. Almost like an instrument you have to know how to play just right. haha

I'd recommend spark plugs wires coil pack and a new upstream o2 sensor

They do accelerate kinda slow until about 4100 rpms or so, atleast mine is like that. I built a bigger throttle body and got better throttle response and a little better acceleration up top, but they dont really start making power until around 4k rpm. The stock hp rating for a 420a is 140hp @ 6000 rpm so you really have to wind them up.