Service Engine Soon light issue and at times runs rough

[Ron 1987 GN]

I'm new to the site, and hoping someone may know what is causing my 2 issues.
First issue: When I put the car in "Drive", as I start to give it some throttle, the "Service Engine Soon" light will come on, but it's dim. As I give a little more gas, it becomes a little brighter. Then, if I give it alot of throttle, it'll go out or if I let go of the gas pedal all together, it'll go out as well. Then, if I give it just a little gas again, it'll come back on dim..
Second, not sure if related to that issue or not, but then I could drive the car for any amount of time (it's sporadic) and my Service Engine Soon light will come on Bright and steady triggering an error code. At that time, the light will stay on until I shut the car off. Once I start the car back up, the light is then OFF and it'll run fine for an undetermined amount of time. It could be 10 seconds, could be 3 hours. It'll all of a sudden kick back on bright and steady again. When this happens, the car idles rough, smells like the sulfur, and if I'm driving around the 40-45mph speed, it'll do the transmission jumping as if it doesn't know whether to go into Overdrive or not. If I give it throttle though, you can't really notice the problem until at sitting idle. At that time, it idles (lopes) like I have a bigger cam in it and smells again. I met a very nice guy this past weekend who also owns a GN. He informed me of this site and also suggested I tap on the Mass Airflow sensor. I've not had the chance to get the car out and try that, but I plan to this weekend. I just wanted to get these 2 issues out there to see if anyone has had this issue before. Thank you for your time if you repost and suggestions / comments.
Ron

 

[turbo nasty]

Hello welcome to the site....I suggest you get a scanmaster first thing. You can also get a paperclip and jump out the diag port under the radio pod and count the ses flashes and see what stored codes you have. That will tell you a few things liked ...tos low, etc

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[Ron 1987 GN]

My neighbor actually sells the Tech 2 scan tools I believe. He hooked up a few years back, but the code we got was (going off memory) a wastegate solenoid code. So, I replaced that and still sames issues. However, I probably do need to have him hook it back up to see if / what new codes are showing. I've never done the paper clip trick, so I need to call in a favor to him.

 

[turbo nasty]

Jump out the upper top two ports. Then key to on ...don't start engine. Now you simply count the flashes . It wil flash then pause then flash. Then repeats that same code three times before moving to next stored code. So if it flashes once pauses the flashes three times that code 13.
Codes for our cars...obd 1 can be found on www.gnttype.org

Which is also a good site to study up on.

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[RmvBfrFlght]

Sounds like the EFI/ECM harness grounds are loose. On a stock set up they are located on the back of the passenger side head.

RemoveBeforeFlight

 

[Ron 1987 GN]

Thank you everyone for the responses. My buddy hooked up his scanner and the code was 32 which is egr solenoid I think. He took the part off his GN and put on mine. Same thing still happened. He then took his ECM computer from his and put in mine. That seemed to have fixed both the SES light coming on dim and also kept from triggering error code 32. So, I have a new computer on order. Thank you again for the help!

 

[RmvBfrFlght]

You should check the resistance of the various solenoids. In the bad ECM a quad-driver fried, which caused the dim SES and the EGR malfunction code. Off the top of my head there is: low speed fan relay, EGR solenoid, CCP solenoid, boost (waste gate) solenoid, and the TCC solenoid.

One or more of them is likely shorted which is what took out the q-driver.

RemoveBeforeFlight