Starts, stumbles, nearly stalls, then fine??

Bigme574

Registered User
For the past few weeks I have started my SC and every once in a while, mainly when it is cold...The car will start, then it will drop in RPM's and struggle to stay idle...it is revived when I hit the gas or sometimes it fixes itself. So, I dont really know where to start on the ignition system. Here is a rundown of the new parts in the past few thousand miles to limit possibilities:

balancer
cam sensor
crank sensor
plugs
wires
fuel pump/strainer
fuel filter
air filter
EGR valve, all EGR hoses/piping
no known vacuum leaks

only ideas: DIS, Coil Pack, or Ignition switch....I would appreciate any input...usually this car doesnt stump me since ive seen it all!!!!

Thanks,
Aaron
 
Last edited:
Fuel Pump

Well, the fuel pump is less than a year old with about 5000 miles on it...its a 190LPH pump from MN12 Performance. I'd like to think that the new part is not bad already, but...you never know.

Thanks for the reply,
Aaron
 
Try pulsing the pump twice and see what the car does. If it IS the pump then it should sound sluggish/slow. I don't think I saw where you had the pump on your new parts list earlier???

Anyways...Good luck


Brad
 
How to clean IAC?

hmmm, IAC...I forgot all about that huge piece of ridiculousness. I did have a similar problem on my 95 which was the IAC wire not plugged in...but it was more severe as you can imagine. Is there A way to clean it safely? I think I used some rubbing alcohol and or windex last time...and it was nice and clean and still worked. Any ideas on what is recommended for use?

Thanks for the replies,
Aaron
 
Been my exp. w/IAC that the issue does not disappear. If I understood you description is only does this for a fraction of time then recoveres and only does it on first start when cold??

Meh...I don't agree with the IAC but I've been wrong with these cars a million times before.


Brad
 
Form my experience a bad IAC tends to stick and cause an initial high idle, then fall back; sometimes that is accompanied by a hooting sound. If you are not getting any CEL codes, then I'd guess you have a small vacuum leak, enough to cause poor idle at low rpm's. Or maybe you have a bad plug or wire, enough to cause a weak spark & small miss at idle; it can be as subtle as a hair crack in just one plug insulator.
 
my sc is doing the same thing right now. when i put it on the otc scaner i have it came up with a throtle postion sensor code along with another that i cant remember. i have yet to replace the sensor its still in the box in the backseat. so i dont know if its the problem.
 
It definitely sounds electrical, due to the extreme intermittence. Maybe a failing DIS ignition module? Mine was very intermittent like that, just before it died.
 
i didnt catch that his does it intermidantly. mine does it every day. im putting in the tps tomorrow or sunday. an ill see if my problem goes away and report back.
 
Back
Top