i need help from the pros..whats wrong with my car?

[WrXeater]

yeah sorry about the long post i just typed that last night when it started to happen and i was mad and just wanted to fix it. basically i have a problem with my car and i need help fixing it..the symtoms are a sliight loss in power and what feels like a missfire but i dont know (under hard acceleration car will jerk for a second and rpms with fall very quickly back to idle then rise right back up to where they were and my check engine light will come on which feels like a just dumped the clutch but im already moving).all this started happening after i put my cat-delete downpipe on......anyone got any ideas or been through this before? thanks

 

[WrXeater]

also..im asking because i just got some new parts (a PERFECT condition 14b (no shaft play, no cracks, just finished porting it) walbro 190 fuel pump, evo 5 front mount and a 1g throttle body that im reaally looking foward to installing and i would hate for something serious to be wrong with my car right when im really about to have fun with it so some useful answers would be very much appreciated. thanks

 

[SpoOLxExO]

Holy eye-sore. I didn't even finish reading that.

Get your paragraphing skills in tact then try it again.

The reason why you aren't getting responses, is because your post is hard to read.

I understand it is frustrating when your car is broken, and you dont know how to put it in a post.

But try and break it down a little bit more for us, eh!?

 

[larsrya8]

That sounds like fuel cut to me... but I'm not a pro. The freer flowing exhaust would be causing it.

The RPMs falling and the sudden jerk of the car would be the ECU cutting fuel and spark in an effort to prevent a lean condition (too much air, not enough fuel). I'm pretty sure the CEL would come on too. The ECU will hit fuel cut whether or not there really is a lean condition; it's more of a preventive measure (better safe than sorry).

 

[Mike1992]

all this started happening after i put my cat-delete downpipe on

You have a rear o2 sensor, its probably bad now because of not having a cat anymore, which in tern is throwing the check engine light.

 

[rob_rousseau]

this sounds like a need for basic maintenance. It is easy to mistake a misfire condition as fuel cut when you've never experienced fuel cut before. I'd look into the ignition system first. Plug wires have caused a problem similar to what you're describing with my car in the past.

 

[crunchymilk]

get new spark plugs and try that first.

NGK BRP7's and gapped at .028

if that doesn't help look into spark plug wire, they may be eroded by now.

If that still doesn't help, I suggest getting a logger, it will tell you everything you'll need to know about your car for a while.