Too fast idle

I think my problem is the EGR valve, it sounds like that's where the hissing is coming from, and it's the only part in that area that I didn't change during the rebuild. Buying it in the morning, will report back tomorrow

Bad hose is my situation and clamps won't work. More to come

Because of how the hose is constructed a home made remedy will not work. Where the two lines come together in a "t" it actually vacuums from the valve cover through to the purge solenoid valve, the line is obviously bad. However, this morning I had disconnected the booster vac line and started the engine (of course I forgot I had disconnected it) plugged the pcv hose back into the original purge solenoid valve and the evap line to the lower connector, and plug. With the booster vac line disconnected, it repeated the horrible starting and idle runs I had been experiencing. When I reconnected this line back to the booster, the idle immediately went high and stayed there. When I shut off the engine, restarted it, the idle was slightly higher than normal, but quickly settled down. I let the engine run about 10 min, shifted the transmission in all drive positions, A/C on, and no stumbling, nor hickup or rise in idle. So you wonder what was the fix? Until a new pcv hose arrives, a little dab of superglue on the "t" fitting lines. Once the lines sealed to the fitting, all, for now is well. I have started and run the engine four times, with great success. Will let you know if anything changes.

Where is purge solenoid located? I'm doing the EGR valve now (it started raining, took a break). Last night while looking at it seemed to be the source of the "whooshing" sound. It's about the only old part left.

The canister evap purge solenoid is just behind the egr valve. Follow the pcv hose behind and under the ignition coils(if u have the 3.1 eng). There are two vac lines one from the pcv the other goes to the evap canister.

Thanks

At a loss. Now what is happening is the engine performance is really bad. When starting, the engine runs extremely rough to the point of stalling. When the engine is shut off and restarted repeately, the problem does not go away. Although when letting the car sit idle for about 5 minutes the idle is then fine. Do you remember telling me something about the coolant temp sensor? Would this be my culprit?

Thanks for this web site!
1999 buick century has high idle. Replaced IAC. Replaced O2 sensor before catalytic. Had it checked for tune up - it was okay.

Don't know what else to do. :Cry:

Please help. Thanks again.

It could be a vacuum leak. Does it have any codes set?

:

No trouble codes.

You will enjoy this.
I"m not sure what fixed the idle issue but, it is gone. Possibly combination of repairs
1. PCV
2. PCV vent tube
3. Evap canister vent solenoid
4. IAC valve
5. Cleaned EGR Valve.

Now I have no codes except for a random engine misfire. My goal at this point is to replace all the wires. The coils all have good fire and I'm not sure what plugs/wires age are at this point. So I will go there. I pray the injectors are good, but that is another issue.
I did have my codes checked at autozone and a P0300 and P0404 hence why I cleaned out the EGR Valve and replaced the seal/gasket. As of Now, I have NO codes. Repeat NO codes from the engine. Even the cylinder misfire code 0300 has not resurfaced. More to come.

I would start by checking for vacuum leaks. With the engine idling you can carefully spray around the vacuum hoses. If the rpm's or the sound of the engine changes, you are getting very close. The vacuum tee near the throttle body close to the throttle linkage is a common place for a leak. :Idea:

very important : be careful when doing this test. Remember the spray is very flammable. (I'm sure that I stated the obvious here, just doing what I do) 8) :roll:

Thanks! I'll give it a try.

I replaced the EGR valve and the Buick ran perfect. The rough idle and poor gas mileage went away; it ran like a dream all week. Today my mom called and told me that the rough idle has returned. Why on earth would it run great for a week and then go right back to having this problem! As I said before I had rebuilt the engine from the heads up a few months ago, the EGR valve was the only part I had not replaced. It was running better than new up until a few weeks ago, now, like you, I'm stuck with this mysterious problem. It runs fine, plenty of power and smooth, but it's idling rough and losing gas mileage. This is getting frustrating!

Here's the situation at this point
I have replaced all 6 plugs
four broke at the ceramics, two had worn tips but suspect bad gap and just old plugs. They had Autolite 606 plugs.
Got the new plugs in, starts and idles fine, BUT, still have surging and misfiring. When the car is running and I'm driving for about 1/4 mile it runs horribly, but after that, the car settles and runs fine. This happens anytime the car is shut down and restarted. Any other suggestions? I have checked the coils, but they seem to be producing good spark. I will take the coil wire caps off and look at the spark in order and see if they seem to be weak at the cap. Then possibly look into either coil, or bad ICM.