2001 Saturn SL1 P0300

[msehler]

Alright, so I have my wife's 2001 Saturn SL1 and a week ago drove it 3 hours away (and back). My wife drove it the next two days running errands and then the Tuesday after labor day (the next day) we get in to go to work and it runs like crap. I take it to a shop and they pull codes P0404 (EGR valve) and P0507 (high idle). They quote me $1000 to pull intake and inspect for clogs, install new gasket, and remove and clean EGR valve (and some fuel system/intake cleaning system). I say thanks but no thanks and do all the work this past weekend on my own. Intake gasket was indeed leaking around #1 cylinder (confirmed via intake cleaner spraying), and EGR was dirty. It still runs like crap and I take it to the auto store for a scan and they ONLY get P0300 (random misfire).
Long story short,
I've replaced:
Intake manifold gasket
PCV valve
ECTS
coolant
spark plugs (NGK)

I've cleaned:
EGR Valve
Throttle body
IAC Valve (it moves very slightly when the key is switched to 'on')
(air filter is clean)
(plug wires seem to test like they all had reasonable resistance (400-900 ohms)

It seems to run MUCH better at higher RPMs, but when I put it into gear it shutters pretty bad and almost stalls. It's acceleration is off the charts slow (up to about 30mph is all I've gotten it up to), and sounds like a tractor back by the exhaust.

Where do I go from here? Pull the cat and see if it was blocking flow? There seems to be pretty good airflow out the exhaust (although I haven't dealt with a blocked cat before). Test coil packs? Replace plug wires?
When first starting up there is a pretty strong odor of unburned fuel in the engine compartment, so I feel it is unlikely it's a bad injector.

Any help would be greatly appreciated.

[fdryer]

There's a possibility of a sticking egr valve that cleaning won't reveal - two motors and and feedback sensor that can't be serviced, possible clogged catcon, and possible fuel issues (fuel filter and/or pump). Try the easy things first.

Cleaning the ignition control module and ignition coils of corrosion may help with erratic misfiring.

Making a temporary blocking gasket to cover ports underneath the egr valve with it holding down the gasket will eliminate leaking exhaust into the fresh air intake manifold. A short drive will reveal whether this works or not.

Removing the front O2 sensor for a brief LOUD drive can reveal a blocked catcon as the alternate exhaust hole allows exhaust to leave.

Fuel filter replacement depends on mileage along with a fuel pressure test to check to see if there's anything to be concerned about. Autozone may have a loaner for use.

[msehler]

I should have added that in there:
2001 Saturn SL-1
~117K miles
almost no maintenance outside of oil every 3K, gas, and tires (except for what I just listed). Plugs and wires changed about 4 years/40K ago (except for the new plugs in last night).

[msehler]

Originally Posted by fdryer

There's a possibility of a sticking egr valve that cleaning won't reveal - two motors and and feedback sensor that can't be serviced, possible clogged catcon, and possible fuel issues (fuel filter and/or pump). Try the easy things first.

Cleaning the ignition control module and ignition coils of corrosion may help with erratic misfiring.

Making a temporary blocking gasket to cover ports underneath the egr valve with it holding down the gasket will eliminate leaking exhaust into the fresh air intake manifold. A short drive will reveal whether this works or not.

Removing the front O2 sensor for a brief LOUD drive can reveal a blocked catcon as the alternate exhaust hole allows exhaust to leave.

Fuel filter replacement depends on mileage along with a fuel pressure test to check to see if there's anything to be concerned about. Autozone may have a loaner for use.

Okay...I made a plate out of home HVAC venting to block the EGR - no dice.

Pulled the front O2 sensor to relieve possible pressure from a blocked catcon - no dice.

Pulled wires (to replace) and remembered about a coil pack/ignition control module test (ICM) I read about...turn it over for a second with no wires, if one pack doesn't have a spark jump, then switch packs. If the spark follows the pack, it's a bad pack, if the spark is the same position (didn't follow pack), it's a bad ICM (ehow.com/how_7788209_test-coil-1999-saturn-sl1.html [I can't post URLs yet]). I did this, and am feeling good about a potential ICM problem (spark stayed in only one position). I plan to get one from a salvage yard to confirm (I've heard Autozone (or similar) tests are not accurate for ICMs).

Sound about right? Both coil packs registered a little above 8K ohms from plug output to plug output (no ignition), which typically indicates the windings are all intact.

[fdryer]

I couldn't explain it any better than what you just described. Perfect ignition system troubleshooting. Used ignition sets are cheaper than new and work just as well.

[msehler]

Thank you for your help, fdryer. It was indeed a faulty ICM. After I got it in, it ran great, but the car threw two NEW codes (I think the computer feels lost without a code), EGR bad flow (still had it blocked by that plate), and camshaft position sensor (I had crappy BRAND NEW wires from Advance Auto. I STRONGLY recommend AGAINST X-act brand plug wires. I was pulling them off the plugs to ensure a good re-seat and the first one (#4 cylinder) I pulled left the metal connection behind on the plug.). Anyway, removing the plate and new wires from O'Reilly's solved it and it's not throwing anymore codes.

Thanks again for your help! I have another question regarding an exhaust hanger (the exhaust is sitting on the frame, but nothing looks broken off), but I'll google it first and if nothing else, start a different thread so as to contain information for people searching.

[fdryer]

You're a brandy new member. Put your car stats into your personal profile so it pops up under your name like most of us have done. Then all you need to do is add any up to date info on posts so anyone can see what's what.

With exhaust issues, it would be better to start a new thread to lessen the confusion from this thread title. Sort of like discussing ad infinitum about killing a U.S. Ambassador this past week, troop build up along with our war ships being dispatched in the area, more saber rattling, and then exchanging the delicate details of oil preferences - nothing to do with the topic.