Contour Enthusiasts Group Archives Forums General Troubleshooting Lotsa strange probs, lookin for help!

Okay, so for about 6 months now I've been having some problems.

1) About 8 months ago, I got a CEL (it still comes on after about 20 sec of driving). The code came up as something like 'EGR VALVE SENSOR READING ERROR'. I think that basically meant the EGR valve sensor is not registering a reading. Big deal, the car runs fine. So I left it. The dealer I later went to said they will replace the EGR valve, about $400 out the door. I declined. Oh and about 3 months ago I pulled off my upper intake manifold and cleaned it well, along with the TB and lower intake. The EGR passages were full of crap so I cleaned it out. CEL still there.

2) Within the last week, the car has idled like total crap. The interior lights flicker sometimes at idle. The revs fall to almost 500 at some points. This happens when the car is hot or cold upon start. Once you pass about 1500rpm there is no more roughness.

3) Within the last month, when I stomp on it, I get a slight sulfur smell. No biggie.

4) Within the last month, my gas milage has dropped to 16mpg or less (I do mostly driving around town). I can barely squeeze 200 miles from one tank.

I am currently running on 93 octane and I've tried Redline Fuel Injector Cleaner, it did nothing. I checked the MAF sensor, I think it works. The car doesn't feel much slower if at all. Hell, it feels stronger.

I think I am suffering from either a clogged cat(s), bad O2 sensors, and/or a bad EGR valve. Anyone care to comment?

Oh and sorry for the long post.

You didn't mention how many miles are on the car but I assume it's more then 50K.

Lets start with the basics.

1) Since you are getting an EGR code you need to check to see if the valve is stuck open.

2) Since you removed and cleaned the intake you need to inspect the plug wires and coil pack for damage. Also all of the electrical and vacuum connections need to be checked.

3) Next check the IAC valve for proper operation.

4) Check the plugs for damage/ware.

5) Get the fuel injectors cleaned by someone with the proper equipment. The stuff you poor in you tank is good for maintenance at best. The only way to clean injectors is to
connect directly to the fuel rail with a nasty blend of solvents not available at your local auto parts store.

6) Do a base engine check Vacuum/compression.

hope this helps

jeff

I have 93K on the odometer. I had new plugs and wires put in about 2K miles ago.

I too am having poor mileage, barely 200-220 miles per tank with a 13.4 gal fill up. I have replaced the plugs,air filter, fuel filter. Scanned the computer and have no pending or regular codes. Have reset the computer several times. I do not have the idling problem you have, I fixed that this summer by replacing the IAC, this took care of the Moose problem. But now since I have the OBD2 Pepper scanner, I have noticed that I am running lean on bank 2, about 14% Longterm trim on average and bank 1 is running lean about 8% longterm trim on average. I have tried to do O2 analysis but since my PCM will not support all the diagnostics capability of the tool, I can only graph the O2 results and see how well the O2's are switching. So far, it looks as if bank 2 O2 is running leaner than bank 1, the switching does not look too uniform, that is, these things are suppose to go rich and lean uniformly and the pattern I see is that they tend to hang on one side or the other from the X axis on certain periods. Although, they are producing acceptable low and peak voltages depending on the circumstances. Both the bank 1 and 2 upstream O2's do this. The O2 monitors hang on the high side with minimal switching. Not sure if this is sluggish performance or the OBD2 sampling rate is just not the best for this type of analysis. The O2 monitors are running a bit rich. This at times gives me cat efficiency failures (p0420,P0430) pending codes which later disappear after a couple of driving cycles. This shows up in one of the scanner screens as having Rear to front ratios above manufacture maximum limits too but later they go away. Egr also fails test there too when this happens, in the open position test at 82% when it is suppose to be 80% max. Later it performs ok and passes the test. This leads me to believe, that I may have a leak somewhere but I do not hear anything abnormal. Therefore, I am just as confused with this software as I was when I did not have it. Have you had yours scanned?

Just a wild thought,

But if the EGR is hung open (in both open and closed loop modes,) I can see the car registering too rich fuel levels because of the excessive exhaust gases.

This may also explain the poor fuel mileage.

Anyway, just a wild thought. Anyone please feel free to tear idea to chreds, if desired.

Good Luck,
David

After you clear the EGR code and check the other items I suggested then you need to clean/replace your fuel injectors. After about 50k mi your injectors are dirty and
MPG drops. At 90kmi they are rely bad. Also, stop using the high octane gas. Over “octaning” an engine is one the worst
things you can do.

jeff

What plugs do you have, and did it start having these problems after they were put in?

Xenotour -- this problem was present before the plugs. The tech kindly alerted me, and I told him I already knew.

mercman -- It is never bad to put too high an octane in a car. Only too low an octane. At least, that's what I learned in auto class.

Not to start another long thread on the topic but here are the facts.

two low an octane causes detonation (pinging). The sound you here is the pistons and cylinder head vibrating. The danger
is blown head gaskets distorted pistons rods and rod bearings.

Using an gas with a much higher octane then required causes deposits on the combustion cambers and valves. It will not cause any “need to rebuild” damage but will over the long run degrade engine performance and mileage. So it's just a waste on money.

An engine's octane requirement is based on compression. Higher compression engines need higher octane fuel to prevent detonation.

Your car will run best if you use the recommended octane.

jeff

sound of detonation is thesound of the fuel exploding. Causes, all those you mentoined, but include, cracked rings, eroded piston heads, melted pistons, burned valves, mented valves, connecting rod failure, crankshaft failure, and crankcase failure.

High octane fuel also has a lower BTU content than lower octanes, thats the reason some people notice less power with 93 vs. 87.