Chronic bogging/popping problem at low RPMs

[SLoW_SHO_316]

This has been a chronic/on&off problem since I got the car in september.

If I'm cruising in 5th gear at about 40-45 mph and give any throttle, it feels like I'm in a vibrating chair, the more I push the trottle, the louder and more violent the popping/bogging becomes. This is existant in every gear at low RPMs (under 4,000) in any condition. Just started, running for 10 minutes, hot weather, cold weather, etc...

I changed the fuel filter/plugs a few weeks ago, and the problem died down a little, but now it's back. Also TPS is new, and MAF is clean.

I get a CEL light every now and then, so I cleared the codes last week and drove around for a few days watching the CEL light come on every now and then.

I pulled codes last night and got a 172/173. The plugs on the car have less than 2000 miles on them. I read them today to see that there's black soot on them, pointing to rich conditions. Also there's little white specs on the electrodes, pointing to lean conditions.

How can my car be running both lean and rich?

On thursday I'm taking the intake manifold off, and cleaning the whole thing, including the IAC and TB. I'm also replacing the plug wires.

What else should I do, or look for? I'm really hoping to get this problem cleared up. It's been a PITA for about 6 months now.

 

[TYSHO]

Off the top of my head, IIRC, the two codes you have are for both oxygen sensors.

Edit: It's indicating that your rear 02 sensor is reading lean(172) and rich(173). Try replacing it!

 

[SLoW_SHO_316]

Yes, but I think the car is actually running lean and rich.

On my dyno graph, anything under 3k is off the chart lean (17:1), and anything over 6200 rpm is off the chart rich (10:1)

 

[Mike Kelly]

oxygen sensor

Oxygen sensors can and will go bad in whatever mode they decide to.
one lean, one rich, both rich, both lean etc etc. Mike

 

[TYSHO]

Yeah, I had the same codes, replaced the rear 02 and was finished. If your car, as in whole, is running rich and lean, then your front 02 would be throwing a code too. Usually when one sensor is only throwing a code, it's the sensor.

Edit: Make sure it's plugged in and that it's screwed in tightly. If it's loose or unplugged, it will throw the codes. BTDT.

 

[SLoW_SHO_316]

Yea, but is my o2 sensors CAUSING my car to run rich and lean? The plugs I pulled were on the front bank. Not the rear.

 

[SHO--ripper]

Is there oil in your plug wells?
Bad 02's will make your A/F

 

[SLoW_SHO_316]

No oil in the plug wells.

Wanna come to Newington and help me rip this ***** apart on Thursday morning?

 

[SonicRiot]

Weird. How are you stomping all of these cars in vids with a broken SHO?!?

Anyway, plug in a scanner and look at fuel trims, long and short term. It's really the only way if you think it's definately a fuel issue. If you can get to NVCC on Tuesday or Thursday next week, I'd be happy to scan your ride.

 

[Sho-Driver]

Bad O2's will make the car run rich or lean for the fact that the computer could see a bad O2 as showing the motor running lean or rich. For this, the computer will correct in the opposite correction.

Yes, but I think the car is actually running lean and rich.

On my dyno graph, anything under 3k is off the chart lean (17:1), and anything over 6200 rpm is off the chart rich (10:1)

172 (R,M) Oxygen sensor not switching - system is or was lean - Single, Right or Rear HO2S - Fuel control

173 (R,M) Oxygen sensor not switching - system is or was rich - Single, Right or Rear HO2S - Fuel control

I think you've figured out your problem....

 

[SLoW_SHO_316]

Would this explain why my car bogs out and pops below 4,000 rpms?

 

[TYSHO]

Yes...

 

[SHO--ripper]

Replacing the 02 sensors is very easy, and fairly inexpensive. I got both for around $75 at advanced auto. I'm at school in RI till friday night.

 

[foshotime]

your problem is most likely oil leacking in to the tube well seals causing the car to missfire. pull out a spark plug wire, all six, and see if there is any oil on the plug wires. if there is your problem is the tube seals and need to be replaced. very simple procedure. inside the valve covers. while your at in powder coat your intake manifold and valve covers. you will also need new plugs ( motorcraft double platinum plugs only)and also new wires, and gaskets all around.

Rich

 

[Sho-Driver]

your problem is most likely oil leacking in to the tube well seals causing the car to missfire. pull out a spark plug wire, all six, and see if there is any oil on the plug wires. if there is your problem is the tube seals and need to be replaced. very simple procedure.

No oil in the plug wells.

you will also need new plugs ( motorcraft double platinum plugs only)and also new wires, and gaskets all around.

He has not stated anything about leaking valve covers, etc. You can use plugs other than the stock Motorcraft plugs. Without knowing the age and condition of the wires, you can't tell him that he will need new wires and plugs.

Don't ignore the codes. That is the best place for you to start, especially since the codes you received seem to go with your problem.

 

[foshotime]

read the technical bulliten from magnecore on fitting plugs and wires

 

[SLoW_SHO_316]

Well I took off the intake manifold, cleaned that with carb cleaner and a wire brush, changed the plugs and wires, put it all back together and it runs great. I have a small coolant leak coming from the TB, but I think I can figure that out. Hopefully the smooth ride will continue and my car wont have this problem again.

 

[Sho-Driver]

read the technical bulliten from magnecore on fitting plugs and wires

For what? Try running stock plugs with nitrous or boost. There are more plugs that WILL work WELL with the SHO(and fit with the plug wire boots). I am running coppers for tuning and iridiums after I am tuned. A buddy in CO is running coppers in his stock SHO as we speak