FYI - The EGR has a flex pipe (I believe going to the exhaust manifold). Nothing to clean there. It's the cast aluminum tunnel between the EGR and the UIM that needs cleaned.

Also, the coil packs rarely go bad, but from my experience, you are better off with an OEM coil (even if it's a salvage one) then the ones the parts stores sell (the few I've changed, I've seen the aftermarket replacements go bad before the other original coils). The coils on the 3100/3400/3800 N/A are all the same coils. Here's a write up done by the Bonneville guys on how to test the coils (I completely intend to do next time I suspect a bad coil):
View topic - Comprehensive guide for troubleshooting Ignition coils : PontiacBonnevilleClub.com

The ignition module is easy to remove AND the most part stores (like Autozone) have a diagnostic tool that can test if it works or not.

As for the head gaskets on a 3100, got news for ya, they can be bad AND the engine run great. I had that happen on my Grand Am. It would run rough for a brief moment when it was first started and that was it. By the time I finally got some help to figure out my problem, from a cold start, the car was leaving large white clouds. On that car, the temp gauge would spike as it built to operating temp. The problem was compression gases were getting into the cooling system (making an air pocket at the Tstat, so it would not open when it should, car was never really over heating). After a 20+ minute drive, if I popped the hood, coolant was being forced out the pressure release on the radiator cap (the compression gases over pressurized the system). As well and coolant seeping into a couple cylinders. Head gasket is pretty extreme and not always the issue, rule out the simpler stuff first!

You mention leaking coolant. Where are you seeing coolant? There are a lot of non-headgasket causes for leaking coolant (which a coolant leak can explain slightly high temps, but still does not explain the performance issue). Since it does not begin mis-behaving until it's warm, I'd what is affected by the temp.

 

Ok. Sorry for the delay, midterms week. Anyway I have done a few things. I tested the fuel pressure to see if the fuel pump was perhaps malfunctioning. Fuel pressure is good, which I assume would mean that the fuel system is good except maybe the fuel injectors. I went ahead and replaced the ignition control module.

I took the air intake tubing off all the way to the throttle body. I noticed some kind of fluid on the inside of the throttle body past the valve(possibly fuel). I'm not really sure if this is normal or not (leaking fuel injectors?). I am going to take the EGR valve off again and check down in the tube headed to the UIM. I did clean this last time but I want to look at it again.

Coolant isn't being forced out of the pressure release when the car warms up. I have heard that if you take the radiator cap off before you start the car (cold start). You can observe bubbling in the coolant caused by the air from the cylinders applying back pressure as you apply the throttle... There isn't any sign of white smoke coming from the exhaust. It actually looks like the coolant is coming from the thermostat or somewhere else right under the throttle body. It is very difficult to tell and I ran out of time tonight. It almost looks like it is coming from the intake manifold gasket (which would suck since I had that replaced).

One thing I haven't done yet and I feel dumb for not thinking of it sooner. I haven't had the spark plugs and wires changed in a while. I didn't really think it has been that long but I feel like I have changed most of the rest of the ignition system, might as well do this too. I doubt the car will make it to a local mechanic to get plugs and wires changed. I have heard that changing those back plugs can be a pain in the butt. Are there any tips of ways to do it? Preferably without having to roll the engine forward.

 

3100/3400 back plugs are no issues. I found on the mid 90's n-bodies I have to remove the 2 nuts/2 bolts holding the coils and ICM down and flop it out of the way. On our '05 Impala with a 3400, I don't have to move a thing, just do'em (by feel).

 

Yeah, changing the plugs wasn't terribly hard. None of the old plugs looked out of the ordinary. The problem still remains though. I noticed two new things that may be a clue.

First of all, when I plugged the battery back in it started throwing a code p0122, throttle position sensor. I replaced that so I'm not sure if there may be a wiring issue or something with one of the other sensors on that circuit. I checked the input voltage to the sensor and it is at 5.0v like it should be. I also checked the resistance range on the output, .6 at idle to 4.5 when the throttle fully open it is a smooth range in between.

The second thing I noticed was that from cold start if you rev it up to about 5000 rpm it will sputter just like it does after it warms up.

 

So now I tested the TPS. It is good, for sure. I tested some of the other sensors on the same circuit and nothing looked out of the ordinary. I started it back up again and it is now putting off OBD code p0403 and p0405. Both pertain to the EGR valve. Oh and it puts off heavy fumes, you can smell it in about a minute after the engine is started. Wow, this is beginning to be frustrating. Anybody else think it may sound like a wiring issue, or could it be the computer is messed up?

 

Unplug your EGR and see how it runs

 

Ok so I finally had the car towed to a shop and fixed. I figured I would put the results up here to help anyone else who may have a problem like this. It turned out to be a bad crankshaft sensor. As it would heat up it would simply stop transmitting to the computer. It is back and running well.

Thank you all for your help.

 

Glad things are running. Thanks for the update. I rarely ever here of that sensor going bad (but sadly it does happen).

 

What's the fuel pressure supposed to be on the 3.1l and 3.4l engines?

 

In the 30-40 psi range, at idle.