tomd_2000formula

Sorry in advance about the long post.

I've got a 2000 Formula with about 94K miles on it. The only mods I have done are Borla cat-back, SLP Y-pipe, K&N filter, airbox lid and smooth flow bellows. The car runs rough around 2500 rpm when at less the WOT and the SES light is on. After hitting this rough spot it continues to fell sluggish until I shift. I had the guys at Autozone scan my codes and the first time they found P0171, P0174 and P0430. I checked the car for vacuum leaks and didn't find any so since the O2 sensors were original, I changed the two in front of the cats (used Bosch 13444). Now here I am a week later and the SES light is back and the car still runs rough. My codes now are P0137, P0157, P0171 and P0174. Based on P0137 & P0157 I figure I need to change the back two O2 sensors (they're also original). But P0171 & P0174 has me thinking I missed a vacuum leak somewhere. I haven't gone over the intake manifold and throttle body bolts to make sure they are still tight yet, but plan to do that tonight. Any suggestions on where I might start looking?

And that P0430 code bothers me. Could it be related to the codes on the O2 sensors? Should I just change the back two O2 sensors and see if that clears things up?

69Muscle

What did it turn out to be?

tomd_2000formula

Not 100% sure yet. I've replaced all 4 O2 sensors and the TPS. O2 sensors had 95K on them already so I figured they were due. TPS seemed to have a dead spot at about 50% WOT so I figured $30 was cheap insurance. Also found a crack in the vacuum line between the throttle body and the PCV valve. After all of that it's running better but still has a hesitation at 2500 RPM. Does this consistently except when I am at WOT, so I am guessing I missed a vacuum leak. I saw another post with a similar problem and they claimed to have fixed it by cleaning off the ground wires. I'm doing that tonight. I'll probably throw in a new battery while I'm at it as the one in there is original and the car is 6 years old with 95K on it.

69Muscle

I had that dead spot. Turns out a sparkplug wire was archin on the engine block. took me a while to find that bugger.

jimmyblue

iTrader: (11)

Have you ever cleaned the MAF since you started
using the K&N?

tomd_2000formula

69Muscle - I'm assuming that spark plug wire damaged. What was wrong with it? I've got MSD wires on my car with about 40K on them.

jimmyblue - The K&N has been on the car since new and it get's cleaned about every 25K. I haven't cleaned the MAF (couldn't see how to do it without breaking the little wires), but I do look at it about a week after I clean the filter. The little wires have looked clean each time I've checked it, but I just used a flash light and my naked eye, so it's not impossible that I missed something. How do you recommend cleaning the MAF?

fonzi_32

any luck? I have the same problem, I have no clue what it is.
Any solutions to fix it?

Vax

iTrader: (1)

This mind sound like a stupid question, but make sure you're injectors are plugged all the way in.

sometimes they can wiggle loose and you won't even know, causing it to throw a misfire, run rough, etc.

Steel Chicken

iTrader: (3)

pull plug wires one at a time too, see if it runs any different.
well, thats an old timers trick. that wont hurt our new multiple coil setups will it?