View Full Version : bumpy idle at stoplight, then check engine light

03-09-2003, 12:38 AM
i was at a stop light tonight and felt the idle become a bit more rough. the rpm gauge moved slighty. id say maybe a 50 rpm of movement according to the gauge. Then i accelerated away from the stop light and the check engine light came on for about 8-10 seconds. I waited till the next light and decided to gas it to check for loss of power. Sure enough, i couldnt even spin the tires in the rain. it seemed to accelerate slow initially, then at about 3000 rpms it would get some power.

any ideas? im guessing plugs and or wires. id bet their pretty old.


Kevin Varnes
03-09-2003, 12:48 AM
Plugs and wires won't set a check engine light though. Scan your computer for codes and find out what made it angry.

07-08-2003, 01:31 AM
my car does the same exact thing but i just changed the plugs and wires if you find any answers let me know:)

08-14-2003, 05:57 AM
I have a 90 SC and mine does the same thing when I come to a stop in gear. I has started doing it a little when in neutral or park as well. As soon as I get some time (maybe this weekend) I'm going to chech some things out. After talking to a few mechanic friends the things I've been told to check for (especially in a supercharged application like ours) are O2 sensors, cats (plugged), and knock sensor (pulling too much timing) to start with. I am also going to replace the fuel filter anyway.
I swapped my stock airbox back in place of my K&N cone filter and that seemed to solve or greatly help my detonation problem.
The thing that really worries me is that it's started in again with detonation between 2 and 3,000 RPM. The last time I had really bad detonation problems I somehow wound up snapping the crank and having to put in a complete long block. They may or may not be directly related, but it still worries me. The engine I had to replace (the car's 2nd) only had 34,000 on it. My current engine (car's 3rd) has a little over 16,000 on it. Like sabre81, I used to be able to light up the tires whenever I wanted. Now I sometimes have trouble even doing that in the rain. If I find anything usefull out, I'll post back.

Randy N Connie
08-14-2003, 09:10 AM
Take the plugs out and see if any one of them look different.
Plugs can and will foul then come back.And the check engine
light will come on with a fouled plug.

This is one off the signs of a head gasket leaking part of the time.
I know I spent $8,000.00 to learn this.

If one of the plugs look cleaner that the rest.Most likely it would
be in one of the rear cylinders.It is worth a look before you start
replacing other parts to find the miss.


05-01-2005, 06:30 AM
Fuel pressure regulator? I read somewhere that if you pull the vacuum hose out of it and thiers gas in the hose, get a new one.

1990 SC

Randy N Connie
05-01-2005, 07:56 AM
That is my impression,If you have fuel in the vac line ,you need a new fuel