01steve

i've been having this problem off and on for about a week now. the other day i was idleing and i turned on my a/c then the rpms dropped to about 600rpm and shortly after the cel was flashing (indicating a misfire).



i took it out later that day and everything was fine. the next day i had to step on it and the car just fell flat on it's face @ around 3krpm then it picked right back up and propelled the car forward.



it did it again last night in 1st gear we left out of the toll booth and 50' later my tire's were squealing followed by another bog-... at which point i started feathering the pedal fore and aft to maintain a decent recovery.



it seems to do this when i'm heavy on the throttle. i've had a cel for quite sometime for the evap system-... after this i also got a code for a misfire on cylinder 3. not too long ago i had gotten some rogue codes for my aftercat 02 sensor (which has had a non fouler on it for quite some time).



before we start blaming the tps (like i did), it's been swapped for a brand new keifco, aswell as the plug wires (today). i tested the iac and that's in working order. i don't suspect the spark plugs as it is an intermitant problem. i intend on cleaning the maf tomorrow. the engine has about 70k on it (due for a timing belt change). with the non foulers on the 02 i'd hate to think it's the cat? maybe the crank position sensor? i'm in the process of buying the 2 sensors for the evap system.



any ideas?

Stocker

If you can determine a more precise set of circumstances that trigger bad running, that would be helpful. Do the misfires occur on all or just one particular cylinder?

01steve

it seems to do it when there are sharp inputs on the throttle-...



the first time it happened i was low on gas (should've mentioned that earlier sorry) but the gas-light was NOT on-...



i've been trying to provoke it since and it has yet to happen.



according to my cel it was just on #3

Stocker

You get the un-fun part then: wait and see what happens, and if you can MAKE it happen. If it only happened on a very hot day, maybe you luck out all but a handful of days of the year.

01steve

actualy for once the weather has cooled off around here-...



it did it again twice today both times in first gear from a dead stop to a pretty enthusiastic start @ 3.5-4k rpms it just bogged held that bog for a second or 2 then carried on it's merry little way.



i sprayed the maf w/ a bit of electric parts cleaner last night-... obviously didn't help.



i have another crank sensor aswell as coil pack but i don't know if either are any good i may try one of those.

Stocker

...did it throw a misfire code those times?

01steve

not that i saw-...



the more and more i think, it's gotta be a clogged cat!



choking the engine out and then when enough pressure builds it blows the crap through the honeycomb causing a surge in power.



my catalytic converter's probably around 6yrs old.



upgrade time!!!!

01steve

cat wasn't it-....



grrrrrrrrrrrrrrrrr better sounding exhaust possible side effect but still grrrrr



still wound up w/ misfires on cyl 1 & 2 just after new cat install-...



i'm currently trying a different (used) coil pack now.



we'll see where this gets me.



edit: just as i hit enter my cel was flashing-...



i'm getting desperate new plugs, new wires, new tps, used coil pack-... word on the forums is if it was the crank pos sensor it wouldn't start (a symptom i'm not getting), sprayed carb cleaner by most vaccum lines looking for leak but no change in idle



i'm getting desperate!



any other ideas?



edit: new exhaust sound is sub-par to say the least. so i spent more money on parts that didn't fix my original problem and now my car sounds (sigh) honda-ish.



i've had less of an issue w/ the bog/surge lately but it has popped up a time or 2.



i also took as much of the maf apart as i could and (again) sprayed it w/ electric parts cleaner.



i did notice the rubber part of the intake(after maf before thottle body) was not as clean as i'd like it to be.

01steve

feel like i'm about to jinx myself but the car has NOT had the bog/surge issue for a few days now!!!



i seperated the parts of my maf and hosed it w/ electric parts cleaner and while i was at it i also cleaned the throttle body, rubber intake tube, and squirted a healthy dose of carb cleaner in the intake manifold.



my question is, i noticed my intake setup gets progressively nastier-... cai is clean as a whistle, maf had some fine dust particles on the inside of the housing, rubber elbow was coated w/ grime on the inside, and tb to match. i have one catch can on the hose that matters (pcv,catch,manifold).



the coupler that connects the cai to the maf is in great shape and clamps are tight enough.



where's this dust coming from?

Stocker

If you put the catch can in without cleaning the intake tract, it could be leftovers from the dirty old days before you filtered the PCV line.