99 EX problems, need some help

[Hektic]

Hey guys, I'm pretty new to the site and would like some help if possible with some problems I am having recently. I have a 99 EJ8 which I was recently doing minor work on and had to reset the computer (battery disconnect) to do it. Afterwards I had to drive the car to get all the ecu monitors back on so I could take it back in for inspection. Basically it was driving perfectly fine for roughly 60 miles and I thought I was in the clear until the other day when I had driven about 7 miles to work and right as I was puling in the check engine light came on and the D4 indicator light on the gauges was flashing and I was having a hard time accelerating. The car is an automatic and the speedometer stopped working also. I'm not quite sure what could be the problem as I've never had this happen before and I'm just hoping it won't need major tranny work. I haven't been able to get the code checked yet but I'm looking for anyone's input on what they think the problem could be. Thanks guys I appreciate all helpful answers

 

[b16lewis]

Get that code, things will go a lot easier

 

[2slo4u]

if it was the tranny, it would be happening all the time, but yes, pull the code

 

[CIVIC_VTEC]

like everyone is saying get the code. i just recently ran into the same problem! but when i figured it all out and looked at the source it was my o2 sensor in my exhaust.. when your o2 sensor no longer works. it sends a message to your computer pretty much saying that your not getting enough air flow through your exhaust... hints why your rpms may be fluxuating, and lack of acceleration. hope that helps.