Hello all,

Got a 92 SSEI with about 125k on it (don't know exact mileage as the dash cluster is going in and out). The behavior I see is that when the car reaches normal operating temps it starts to idle very rough - dipping rpms and shaking the car a bit. I am fairly new to working on cars but have a little experience.

Some basic things I have done so far:
Replaced plugs/checked wires.
Checked PCV valve
Replaced Serpentine belt (was worn)

I am looking for any and all suggestions for what the problem would be. Used to have an engine light on but after changing the plugs this went away.

Thanks

No thoughts anyone?

I have another sympton that I think could possibly be related. The engine seems to miss a little when driving with the gas held steady. Its not like stalling out or anything but it is noticeable. I found this thread which seems like a similiar problem but no solution is really posted:
https://www.gmforum.com/t255152-2/

I am gonna pull off the dist caps and take a look maybe tonight or tomorrow, but anything else I should check? I was also thinking of changing out the fuel filter but I can't seem to find the fuse to turn off the fuel pump?

Also I see people saying check the EGR but I thought this model didn't have one? How can I tell.

I really appreciate any and all response. Thanks.

Well I tested the coils per instructions on the how to guide (thanks Dan). All reading 5.3k Ohm so I believe that is good. Also I pulled one plug at a time and got arc on all the connections so it looks like the coil is good.

Next thing on my list is to get a new fuel filter as soon as I can figure out how to disconnect the fuel pump. If anyone has an idea of where this relay is that would be great. I found some under the hood but they are not labeled as far as I can tell.

actually they are. pull the black cover off and look inside of the cover. it'* even color coded.


there is a fuel pump relay under the passenger side kick panel dash area.
and there is a diagram under the kick panel as well. remove the kick panel and turn it upside down.

kinda rough but does give you an idea.

Thanks toddster the diagram helps a lot. I will take a look at it tomorrow and see if I can find it.

OK so I did find the relay... unfortunately I can't seem to pull the fusebook out (the glovebox is kinda in the way). So how do you pull the relay without tearing about the glovebox? Do I try to reach up there and pull it out? Thanks for the help

Thats what you need to do, reach up there. Or at least that is what I've done. Don't think pulling the glove box out will help.

Sorry for not responding sooner, crazy busy but was finally able to replace the fuel filter.

OK so here is a quick recap of what I have tested/replaced so far:

New plugs and wires
New Air and fuel filter
New PCV Valve

I tested the MAF by uplugging it and starting the car. Car ran worse, so I believe MAF is OK?
I tested the IAC by removing it and running car. Car idles fine but at about 1200-1500 rpm. What does this mean? I also cleaned the IAC (tip was black).
Tested the TPS via Dan'* how to/ resistance was fluid through range.

Any ideas for further testing/diagnoses?

I am thinking maybe 02 sensor??

Thanks guys.

If the O2 is old you should replace it. It might help. But seeing it'* giving you trouble when hot I still think it'* the IAT sensor. Also clean the MAF. Have you done a seafoam top clean? I've seen this do good things in the past.