Missing under a load

My 2000 focus zx3 standard started missing when I would first take off or right after I would shift gears (under a load). It acts like the electrical
system is shutting it down. At first I thought it was the throttle position sensor because it would act up (stumble) when I would give it the gas. If I move the gas peddle slowly it will rev up fine. The speedometer bounces around crazy when it acts up and I can hear a popping sound in the speakers. I had a new sound system and alarm system installed about two weeks prior to my problem. I brough it to the ford dealership and they could not fix it and suggested that I bring it back to the audio installer. I did this and they rechecked all the ground wiring and said that they use their own grounds and everything looks good on their end. No check engine light is on. I pulled the wire off the TPS to see if it would run any different and it did so I guess its ok. The check engine light did come on at this point and autozone confimed that when they plugged in. I bought a new battery (675amp), plugs and wires, and fuel filter and it has helped a lot but the problem is still there. Should I replace the coil and TPS anyway? One autozone employee told me that I needed a 1000amp battery because of the ampifiers in my car. Any truth to that? Also I just noticed that when the engine is under a load it pings and maybe a knock sensor is shutting things down. Anyone have any thoughts.
--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/ford-focus/200512/1
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The only thing that occurs to me is a problem with the voltage regulator/alternator. To check that you would need to mount a voltmeter and go for a drive.
If that's not it, I suggest you post it to a bigger, more generally technical newsgroup such as rec.autos.tech or alt.autos.ford.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I did have the voltage regulator/alternator checked and it's ok. I will post to a larger group. Thanks.
Dave Gower wrote:

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/ford-focus/200512/1
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
This problem can appear when in second or third pulling away (Fast Acceleration), possible fault in engine management module, not advancing the spark enough under acceleration causing a stutter / missfire. Hope this helps.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
This problem can appear when in second or third pulling away (Fast Acceleration), possible fault in engine management module, not advancing the spark enough under acceleration causing a stutter / missfire. Hope this helps.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.