Okay, it was nice today so I decided to take my doors off and ride around town...well I decided to get on it a little bit, not full throttle or anything just enough to hear my exhaust. And at about 3000prms, she starting losing power, and what felt like a slight misfire.

Pulled into a gas station, and put it in neutral, checked under the hood, and revved it up, nothing, no misfire or anything, I even put it in 2LOW and drove around the parking lot at 3k...nothing!!! Thought it went away.

Again I decide to get on it, and same thing, misfire/loss of power!!

Then on the way back home, started doing it at 2500rpms!!

Now its got a rebuilt 22re, bored 20 over, with about 300miles on it. New dist cap, rotor, spark plugs, spark plug wires, air filter, and fuel filter. 02 sensor replaced bout 2 years ago, along with new cat!

While searching here I came across two possibilities, plugged cat, or fuel pump.

Now the plugged cat seems probable because of the poor running condition of the previous motor (ran super rich, burned butt loads of oil), and the fuel pump also seems possible because of the fact that I dont think its ever been changed!

What are the best ways to check these things...I havent seen if any codes have been stored (too dark to do it now, but will tomorrow), but the check engine light has not turned on.

These symptoms sound just like the ones I had when the 02 sensor went out, just not as bad!!

Any help would be nice!!??

 

If you get it above that RPM, does the misfire go away? Does the misfire happen if you slowly accelerate (is that an oxymoron?) through that RPM range, or only happen at wide-open-throttle? Does it make a difference if it's cold or warm outside? Do you hear any detonation or pinging when it does it?

 

It misses all the way up, 3500+. I havent really done a full throttle test, because im still breaking in this motor. It was warm yesterday, Its a little cooler today, so I will go an try it out and see if it still does it. I had the doors off, so I didnt hear any detonation or pinging, but I will go drive it today with the doors on and see... I am also going to pull the codes to see if there are any stored!

 

Bump for abe!!

 

Well... any codes stored?

 

Well I got 2 codes, 24 and 31. Which are Intake air temp signal, and air flow signal of vaccum swith signal.

So this leads me to the VAF, right? My original shorted out internally a while ago, so I found this one in a salvage yard. Could it be that again...I am going to test it once I get some money...my mulitmeter broke a long time ago!!