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ok ive searched everywhere for weeks and still nobody close to my problem...to start i have a 92 with a DE and full msd ignition. at night with the lights when i come to a stop it stumble and the tach falls to 0 but stays running. this only happens when i hit the brake. i checked and rechecked my wiring and everything is wired correct, soldered, and covered with heatshrink. it doesnt do it at all only in the day. i had the alternator checked along with the battery at 2 different places and they are fun. but as soon as they put the load on the engine with their machine it also does the same as stopping at night. there is no problems throught the rpm band or any other effects. before i put the msd in i had just the coil and hei mod and i thought that was the problem so i added a 6AL and its still doing the same. ive ruled out vacumm or any other leaks since its not doing it in the day time. could the egr be causing these problems because that is the only code i am getting but somethign just isnt right with it doing it only with a load on the charging system. if anyone has any ideas or anything im pretty much open to anything right now

Its your alternator.. more specifically.. its the voltage regulator inside your alternator. Same thing was happening in my RS. The voltage output of the Alternator was fine.. but at night with my lights on.. if I hit the brakes.. everything would dim and the idle would stumble. Do yourself a favor.. upgrade to a Millenia alternator.. you can find them on e-bay all over the place cheap.. but you will need the plug from the millenia wiring harness... same number of wires.. but a different plug shape from ours. Btw.. the stock GS alternator is a 90 amp alt. The millenia is 110 amp. Cheers

Tunes67

well i changed out the alt with a good one and still no luck.....its beggining to be a cluster. its still stumbling with the lights on or if you turn the blinker on everytime it flashes the rpms dip down. this is only at an idle its not doing it at higher rpms. i really have no clue at all

Try adjusting your base idle screw. It will be a little screw that the throttle bracket sits against. Basically it will not allow the throttle position to go any lower physically.

Did you buy a new alternator or just swap in some used alternator? You might also want to upgrade and or add more ground wires. They are available in kits if you want. Use the search you will find lots of info on this topic.

Tunes67

its a new alt..... every sensor is fine the tps is adjusted idle is adjusted... im going to try more grounds and see if it does work

I have also heard of the main charge cable from the alternator to the battery corroding and developing resistance.. just something else to check.

Tunes67

I agree with Tunes it is in the charging system somewhere. Either grounds or poor voltage regualtor. When they are rebuilt it is common for the rebuilder to use the cheapest regualtor they can find. You could try a second inline voltage regualtor (which does work and has been proven by several car mags on the dyno to even add a few WHP).
If those two things don't work out then try the larger Millinea alt, but 90amps is pretty large for a stock disty anyway.
Don't mess with the idle. It might work, but is not a real fix and will screw with the general performance of the motor.

Oh snap.

I just unstuck my strut today, and i took her for a spin. And guesse what? I pull up to a light, put the clutch in and the rmps stumble, and drop and the engine stalls. Weird. I'm assuming its the alt as well, strange. I'll be getting a new one soon i supposed.

Just becasue it studdered doesn't mean that you need a new alt.
You need to check for vaccum problems, TPS adjustment and that the neutral switch is good before you get hasty.

tintdude69 wrote:ok ive searched everywhere for weeks and still nobody close to my problem...to start i have a 92 with a DE and full msd ignition. at night with the lights when i come to a stop it stumble and the tach falls to 0 but stays running. this only happens when i hit the brake. i checked and rechecked my wiring and everything is wired correct, soldered, and covered with heatshrink. it doesnt do it at all only in the day. i had the alternator checked along with the battery at 2 different places and they are fun. but as soon as they put the load on the engine with their machine it also does the same as stopping at night. there is no problems throught the rpm band or any other effects. before i put the msd in i had just the coil and hei mod and i thought that was the problem so i added a 6AL and its still doing the same. ive ruled out vacumm or any other leaks since its not doing it in the day time. could the egr be causing these problems because that is the only code i am getting but somethign just isnt right with it doing it only with a load on the charging system. if anyone has any ideas or anything im pretty much open to anything right now

Try your air idle control sensor had a mx-6 with the same prob. did everything tuned it up cleaned out the TB and still nothing!! So I finally wound up taking it to my mechanic and he ran diganosicts on it and it come back air idle control valve or sensor and yes mine did all the same things also in the day crank it up and turn on the A/C and a few other electric devices and it'll do it to. Usually you can turn up your idle and it will help but not stop it till you fix the prob. Also really gonna put a damper on your hopes the cheapest one I found for my mx-6 was $400.00 USD. Needless to say I sold the car shortly afterward.Also check your intake pipe for cracks duct tape works pretty good for a quick fix.