Helping a friend get his 1999 GSR running. Approx 100k miles on the car.

It starts but idles very low at like 400 RPM and the engine sounds like it's running on 2 or 3 cylinders. The engine shakes violently. He ran the OBD2 code and got a cyl 4 misfire.

I checked the spark plugs and they were very black.

He told me sometimes it runs it pretty normal, but today it definitely wasn't working right.

Things he changed:
Fuel Filter
MAP sensor
Spark Plugs
Spark Wires

Any ideas?

 

do a compression test first...

cap, rotor, ignitor maybe next

make sure o2 sensor is working right

 

compression test then i would check coil or ICM

 

reset the ecu after!, just unplug it for a few seconds and plug it back its located right where the passagers right foot is behind the pannel!

 

Thanks for the help guys, I really appreciate it.

So next we will do a compression test and if that's good we'll swap out the Dizzy (take care of cap, rotor, ignitor/ICM, coil).

 

UPDATE:

He took the distributor to a local auto store and they tested the Coil and Ignitor. They both checked out ok (well the Ignitor first looked bad, but they tested it 4 more times and it passed every time after that.) He replaced the rotor even though it looked ok, but it didn't help. They didn't have a cap, but his looks fine.

Today the GSR would not start at all, so we did a compression test with a cold engine and got about 200 psi in each cylinder.

We reset the ECU and now there is no Check Engine light, but it still won't start. It seems like we are getting fuel because the spark plugs are wet and smell like fuel, I don't think we are getting spark... What's next?

 

FIXED.

My friend told me there was a bad fuse - that's why he wasn't getting spark, then it ran bad because a wire going to the distributor harness was exposed and not making a good connection and had to be cut and replaced.

Car was down for 6 months for $3 in parts!!!

 

cool you got it fixed, and thanks for posting what the problem was

 

what fuse was it?