1996 Century Ticking & Sluggish

1996 Century Wagon 3.1L V6

Symptoms:
Uneven idle - surges and nearly stalls
Loud, consistent clicking/ticking noise around top of engine
Occasionally stalls while shifting to reverse or drive
Very sluggish acceleration on the road, bogs down trying to go up hill

Any ideas would be appreciated.

injectors will make a ticking noise try running some sea foam in your tank to see if it gets better and also could be the tps (throttle position sensor) or cat converter or egr. can you smell anything you haven't smelled before? one more thing cps witch will throw your timing off.

A bit more detailed information

Radiator was changed back in July. Service Engine light has been on since.

Ticking noises in top of engine started about 2 weeks ago, with no other noticeable symptoms

Starting today:
Uneven idle - surges and nearly stalls
Occasionally stalls while shifting to reverse or drive
Very sluggish acceleration on the road, bogs down trying to go up hill


Took the car to Advance Auto and pulled the codes:

P0300 Multiple cylinder misfire

P0401 EGR

injectors will make a ticking noise try running some sea foam in your tank to see if it gets better and also could be the tps (throttle position sensor) or cat converter or egr. can you smell anything you haven't smelled before? one more thing cps witch will throw your timing off.

I get a faint smell of unburned fuel from the exhaust. The ticking definitely sounds like it's in the area of the injectors. I also took off the oil cap and listened inside the valve cover and didn't notice an increase in the sound level there.

I get a faint smell of unburned fuel from the exhaust. The ticking definitely sounds like it's in the area of the injectors. I also took off the oil cap and listened inside the valve cover and didn't notice an increase in the sound level there.

I had similar problems with both my vehicles and found it was the fuel pressure regulators. On the buick it is found at right side of engine (facing car) at end of valve cover(15 minutes to change). On '88 Dodge Caravan it is left side of engine under intake manifold(about 3 hours). On buick it was found by diagnose and having rich fuel mixture as possible cause. On Dodge Caravan it was fuel smell and pulling vacuum hose from end of intake manifold and fuel spilled out.

Also, Changing fuel filter will smooth out idles on most cars with high miles. This caused rough idle on Buick.

Doing some digging, I've tried the following:

Removed EGR valve, cleaned orifice below - it was rather clogged - EGR valve clicks when shaken & the valve piston moves freely when depressed - put EGR valve back in with new gasket - idle roughness improved but still bogs down under load while driving

Replaced the front 3 spark plugs & wires - no difference at all - hesitant to attempt the rear 3 as they are very difficult to reach and doubt it will help

Checked PCV valve - removed from valve cover, idle improved, put finger over end, got suction, idle got really rough, removed finger, idle smoothed out again, put PCV valve back in & back to original condition

Listened to fuel injectors through a screwdriver, all seems to be clicking away normally and could not distinguish that the overall loud ticking nose was coming from any one of them

Removed Air inlet duct - no change

Removed MAF sensor lead - idle improved - no change while driving

Removed Fuel Pressure Regulator vacuum line - has vacuum - covered with finger, got suction, and idle got rough, removed finger, idle returned to previous state.

Things I haven't been able to test that could be suspect:
Fuel pressure
Timing
Cylinder pressure

Upon further investigation of the ticking sound I removed the oil filler cap from the valve cover, and now hear a pinging sound inside. I also don't see much oil up there and I'm not really sure how much should be seen. I can clearly see 2 of the valve springs up there and they seem to be operating properly.

I am beginning to suspect that either the oil supply is clogged somewhere or it jumped timing and bent a valve. I'm not sure if this is an interference engine or not.

It sounds like your EGR valve needs to be replaced. The EGR pintle should not be easy to depress as it is spring loaded. The idle improvement when unmetered vacuum is introduced into the system sounds like you have a rich condition, possibly the EGR valve. Also as it boggs under load, if the EGR pintle has no resistance on it, it is probably allowing excess exhaust gas into the manifold. Also the EGR valve should not "click" when shaken.

Do try a fuel pressure test with and without the fuel pressure regulator vacuum line attached. Without the vacuum line attached fuel pressure should increase. Fuel pressure should be:

Key On Engine Off: 40-47

Typical Idle: 30-44

Hope this helps

No change in status yet. I was not able to work on the car over the weekend. I did, however, just pick up a used EGR valve from a salvage yard. It behaves exactly like the one already on the car though. It rattles when shaken and the pintle is not hard to depress at all, so I'm not very optimistic about this fixing it.