CDNeh

Here is my issue:

2002 MP5 Ran GREAT with no mods.. installed the first mod. Cold Air Intake. and Man it sounded nice.. seemed like everyhting was good.. 3 days later, my Idle started to drop.. get that nice little shakin in the car.. Ifgured mass air flow was off, leakin or something.. so i check all connections, tightened everything again and it was good..
Seem like every time i have my car starts cold, she idles High.. then, when she is warm, my idle drops to almost 500rpm to ALMOST a stall.
And now, check engine light is now on.

Any suggestions, commects, ideas why things all of a sudden went Bonkers?

ZOOM_X_TWO

I have the EXACT same problem, I am running completely stock except for a custom modified SRI, soon to be a monsterflow SRI. It idles high, almost 2000 rpms, then dies down and almost stalls. I also removed the OEM airbox setup, and reset my ECU immediatly after it, and then again when I filled up with a new tank of gas.

Any suggestions on how to fix this?

-Brad.

centsless

reset your ECM..
take the negative battery cable off and step on the brakes for about 30-45 seconds, then reconnect. Gives the ECM a chance to re-learn its idle.

ZOOM_X_TWO

As you can see I have tried that numerous times...any other suggestions?

Thanks, Brad.

CDNeh

Now for my dumb question (first import i have had, love the luscle cars), the car shoudl be running when i do this? I know.. Not used to the computers on the car. Good old 350's is th easy way to go.. *grin*

Roddimus Prime

if you try removing your negative cable while the car is running you will be in for a treat.

with the car off......remove the negative cable and press the brake pedal to allow any stored electricty to drain from the ecu....this is like resetting your radio stations...it forgets what it had and when you hook it up again and start it up it rechecks with every sensor to make it's running adjustments. With the increased air flow its a bg deal.

Omron

cough cough... spark plugs lol ummm did I say that...

well if you have a ruff idle, check your install any plugs or wires that you might have changed... on my honda civic I had some work done and plugs were inspected, but found out they were not seated exactly right... we checked it, and then re seated them and my odd ruff idle was gone... it happened very similar to how yours did but an addition was when switching into Drive (auto tranny) the RPM would drop dangrously low as well.


Hope it helps...

Omron

One more thing, see if you can find a friend that has a Diagnostic tool, if not and your not far from the brampton area, we can hook you up to my Autotap software and we can see what fault codes come up. and we can monitor your ignition systems.... we can watch the idle and see what might be going wrong...

I am waiitng to get my tool back from my friends garage in Ottawa, but I am ordering another standard kit soon in the next few days...

Rock on dude

jusbo20

AutoZone will check for codes for free too.

Da P-Funk!

How about the notorious EGR valve? It would (AFAIK) give the same symptoms. Did you clean the MAF with electrical cleaner (it might have oil from the filter on it)?

macdaddyslomo

try cleaning the MAF....alot of times when swapping to the SRI it gets dirty and that creates probs..spray it with contact cleaner

Omron

i have seen this 3 times 2 of the time, it was a problem with an injector, one was found by mazda dealership, the other was at my friends garage taking everything apart,

its possible if non of the other solutions worked, to consider that you have ap roblem with one of your fuel injectors,

my friend #3 injector had problems, on the one car, doing a cleaning fixed it, remember under throttle your car is running on what ever fully working injectors you have, but at dead idle, a missfiring or poor firing cylinder will be dead weight to your engine, and possibly bring your engine to its knees.

its only a possibility, but i have seen it myself, so i thought i would throw it out there

Omron

any who there are different types of injector cleaners of different strengths, if its clogged, (some how) even though its recent new car, try a very strong cleaner and fill her up with 89 or 91 octane and see if she will fly again, or do a low dose and giver her some strong revs for a while.

2nd possibility you could have a failure, even more unlikly but still possible, take it in to mazda and see what code comes up, for the error

djchazzychef

I had the same symptoms with my p5 and it ended up being a faulty EGR valve (just after 12,000mi).

Stueck

Vacuum leak, mine did that.