hiTmanhiT

Hey guys!
Just recently bought myself a 2003 Ford Mustang GT with 122k miles on it.
It is working just fine, but got some small issues that I was hoping you maybe could help me out with.

1: Every time I start the car, it seems to be running dashboard diagnostics. Every gauge goes from bottom to top like 2 times before it shows the real-time indications. What could the issue be here? Could something be failing?

2: It's got the original mach speakers in it, but not the original radio/stereo(it seems to be some cheap Jensen-stereo)
But the sound in the speakers are REALLY crappy. It is completley without any bass to it. I got a friend with the same car, but the original stereo, and it sounds ALOT better than mine.
Could it just be that the stereo is bad? I got sound coming from all the speakers, but it seems to be lacking bass completley.

3. Sometimes when I start it when the engine is still warm, for example if I just stop at a gas station or store, I have to crank it for about 3-4 seconds until it goes up to regular idle rpm. What could this be caused by?

Also, I am all new to cars, especially Mustangs, so I do not really know alot about them.

Thanks in advance for all your help!

Shampue

** In before Cliffyk **

Does the idle run low RPM and run rough at times? Replace your IAC Valve.

The IAC Value for your year Mustang is approx $80 @ O'Reilly's Auto.

As for your Mach460 issue... You could have a blown amp or some chimpanzee installed your radio. Check to see if the stock harness is still in tact. I also have the stock radio for sale in perfect condition. $50

MCxQubed

1. Check the battery because I believe the gauges sweep when the battery is low

2. Your friend could have Mach 1000, but my stereo had pretty much no bass before I put a sub in it, the sound quality is great tho so idk what it could be

JeremyB

My stereo had only highs when I first got it, had pretty good quality, just no bass, ended up being the rear amps were blown which controls the lows, you can get a pair on ebay for around $80 if you have some patience. To check that the amp is blown, check for voltage to the amp first. If it isn't there, then you have a wiring problem. If it is, most likely the amp is blown. I have also heard where the universal harness plugs into the stock wiring harness, the pins can get bent and not go in correctly, something to check out.

cliffyk

It could well be a bad battery as suggested above, check the battery voltage at the connectors (not the battery posts) while cranking the engine; it should not drop below 10.5V, if it does the battery is not fully charged or is failing.

However also check fuse #21, 5A, in the central junction box (under the dash). This fuse supplies hot-at-all-times power to the cluster, if it is blown or not there, the gauges will sweep as you described on start-up. Apparently some feel it fashionable to pull this fuse so that the gauges will sweep--"like a Honda" or some such drivel someone once said.

There are a multitude of possible causes for this, ranging from poor installation to a defective component. Your best bet is to dig into it yourself, or find a good automotive audio shop.

If "crank it for about 3-4 seconds until it goes up to regular idle rpm" means that after a short stop, with the engine hot, you have to crank the engine for 3-4 seconds before it starts, then this is a somewhat common issue especially in hotter climes--like here in Florida.

I believe it to be caused by heat soak warming the fuel in the rails and causing what used to be called a "vapour lock" type situation. The only fix I have found is to richen the commanded high ECT AFR in the tune's Cranking A/F ratio function:



You can see here (the stock tune values are in the right-hand columns) I richened the AFR at high coolant temps from 13:82:1 to 13.20:1. I have used change on a half-dozen GTs to pretty much eliminate the hot start issue.