Makes, sense, a clogged cat will offer an exhaust restriction which would be more pronounced at low RPM when exhaust emissions are relatively low. It might explain why it happens during tip in acceleration at low revs.

 

Ok a bit more info, I adjusted my valves which were way out of spec. The intake was loose and the exhaust was tight on every cylinder. I am waiting on my gaskets so I have not started it yet but they valves are now in spec (.009 on intake and .010 on exhaust please let me know if I have that wrong for whatever reason.)

Also, when I read the plug color when I pulled them. These are plugs I put in last week and they are all white now, which means running lean right? So if I am lean across all cylinders and clamping the FPR hose increased power does this mean I have an issue with the fuel supply, either the regulator or the pump?

Lastly, is there any way to check the cat?

 

Use the number on the hood, it's not easy but getting them right on the money is best. The hardest to do is intake on Cyl 4, rock the rockers back and forth and make sure they all have the same little tappy noise, that's how you can also gauge that you adjusted them properly. When they're all on the money you can hear the valve train(barely and you have to try) but it all flows together like it just blends into the engine note.

Btw does your oil have a bit of gasoline smell to it? I ask because O2 sensors usually last around 100,000 miles before they start getting lazy. Mine did, and I would occasionally see black clouds and my oil started smelling like gas. I changed the oil and the primary O2 and it hasn't been an issue since.

 

I checked for that today but forgot to mention it. The oil has no gas smell and the oil is half down the Xs which I believe is half a quart (correct me if I am wrong), I know I have put at least a 1000 on it since my last oil change.

The other thing was the week old spark plugs are white which is making me think that the engine is not getting enough fuel. I have been studying the best I can on this and if I understood correctly, if the regulator was bad then it would be too rich and if the pump is bad it is too lean is that right? But the O2 sensor helps the ECU know what AFR to use so if that is off it can mimic the symptoms of either the FPR or the Pump being bad. Does that sound right?

I was looking into the symptoms of both of those going bad and one issue is bad startup which I have been dealing with for so long I didn't even stop to think that might be part of this problem. Also it said that with a bad pump IE not enough fuel it would stumble under load, like when I was accelerating in too high a gear. So I am guessing that it is either the pump or the O2 but I am not ruling out the FPR.

 

FPR failure is not common on these cars, it's cheaper to replace the fuel pump than the O2. Both are known to go bad especially with cars that sit a lot because there isn't really a fuel filter, other than the sock. There is but it doesn't really filter anything.

The OEM O2 sensor is pretty pricey, there are cheaper alternatives. I've had good experience with the Denso O2 they sell on Amazon and Rock Auto etc. They also sell cheaper versions where you splice the new sensor to the existing harness wires. When changing the O2, just remember all the tabs are locking tabs you just have to push somewhere and they'll come off pretty easily.

http://www.amazon.com/Denso-234-4124...uckduckgo-d-20

 

Ok, So I am thinking I will end up replacing the fuel pump and then maybe the O2 later. Is there any reason to stick with the stock type Fuel Pump or can I just go ahead and get the Walbro 255LPH?

My car is basically stock but I have heard the Walbro will work with a stock setup.

 

It can be a real pain to do so go with the upgrade now so you won't have to worry about it later if you go FI or more power NA.

 

Right on. Yeah I have been looking at the installs and it looks tight, don't think I would want to do it many times.

Thanks Reckon

 

I adjusted my valves and the car is running better. Under normal driving it no longer bucks/misfires but under load it will still buck. This makes me think I have been treating symptoms and not the problem. I am getting a Walbro 255 and will see if that fixes it, if not I will try the O2 sensor.

Now my idle is acting up again though... its always something.

 

Another update on this. I replaced my fuel pump with the Walbro 255 (can't believe it plugs up without modification that's awesome) the problem seem to still be there. However, I did notice a power increase and the startup was a lot easier so it was not time or money wasted.

The only two other things I can think to try would be the O2 sensor as Slowcrash suggested and replacing the cat. I'm getting a T.P. from a local guy this evening so that will most likely be the next thing to try.

I'll keep this updated in case anyone else has this issue.

As always any thoughts on the subject or advise is appreciated.