Howdy Gents,

Just bought an 01 ssei 3800sc (73k miles) and am experiencing what best can be described as surging. The problem occurs in 4th gear at around 2000 rpm when I push the gas pedal down slightly. The car will surge or buck back and forth and rpm will fluctuate at2000 +300 -100. If I let of the gas or press the accellerator down further the problem stops. Its almost as though the car can't decide whether to downshift or stay in 4th gear. This problem also occured in 3rd gear and only when the engine is at operating temp.

I've studied the T/* guides on this forum and started with checking the MAF (wires were intact) and cleaning the wires as well. I put in a can of seafoam when I filled the tank today just for good measure. I picked up bosch plug wires and autolite iridium oem equivalent plugs which I will change out this weekend. If these are a bad choice please let me know.

Question 1- Is there a way to test the o2 sensor and egr valve. I hate to fork out the cash if those parts are good.

2- Are the spark plugs at the rear of the engine best accessed fom the top or underneath.

3- What is the best next step to take in troubleshooting. I'm hoping to find the problem asap. We might need to take a long road trip soon. (Grampa is pretty ill, might pass away soon).

My thanks in advance to everyone on these boards for their help.

On mines i changed the plugs from the top. I pretty sure the rack would be in the way from the bottom.

I think I know exactly what your problem is. Read this. https://www.gmforum.com/electrical-133/tcc-solenoid-switch-284972/

I tried the TCC test on the way home and I did get the RPM rise so it looks like the problem is somewhere else. Going to check out some of the engine electrical tonight and see what happens

I tested the following tonight per this forum'* T/* guide

TPS resistance check, OK
TPS signal voltage, OK
MAF voltage, OK
Fuel injector voltage, cyl 1,3,5 all OK wiring looks good as well.
Fuel injector resistance, cyl 1,3,5 all three had 13ohms ea.
The car starts, idles fine and the SES light hasn't come on at all to indicate a latched code.

So no problem found yet. Is it too early to make an educated guess at what the problem might be? I still have yet to replace plugs and wires, and check the coils.

Get the car scanned for OBD codes.

Just had the car scanned for codes- No codes found. Tonight I plan to test #2,4,6 inj volt and resistance. I listened to the engine w/ hood up and didn't notice any ignition related noise. (like a spark jumping through a bad plug wire) Looks like she'* gonna throw me a challenge.

I was looking through the engine T/* guide and wasn't sure what this means. "Scan car for LTFT watch for significantly negative or positive range."

I'll change the fuel filter and check fuel pressure this weekend along with plugs and wires. Is it worth the time to pull the egr valve to see if something is sticking?

I had a few minutes to spare to check the coils. The secondaries on all three tested ok but the primaries on all three showed 0 or short. I'm sure that I've got the test wires far enough into the slot but right before I get the 0 reading the meter flashes a resistance value. Am I possibly doing something wrong or could all three packs be bad?

Mist your wires with water turn off lights and watch in the dark for any flashes.

You need a scanner to scan for LTFT, so don't worry about that.

If you have 0 on the coils it wouldn't run good at all, so you might not be testing them right.