Misfiring is driving me nuts!!

[Merlin]

Whenever I accelerate relatively fast it starts bogging down. It is a very sharp misfire like it loses electricity for a very short time. It does not happen in idle or rarely when it is at high RPMs. It is mainly when I try to accelerate from a gear below 3000 rpms and it is worse in the higher gears. No warning light has come on the dash board either.

I have replaced my old catalytic which was completely cracked inside for fear of clogging of exhaust. I replaced the air filter, wires, and the spark plugs (hell of a pain in the ***). The misfiring went away for a few weeks and then it has slowly started up again and is slowly getting worse.

What could this be? I am open for ANY suggestion right now.

[99davenport]

coil pack? did you see any corrosion around the tips of the coil pack when you took it off?

[99davenport]

might want to run a volt meter to it also there might be some resistance in the wires if its only happening every once in a while

[Turbo V6 Camaro]

sounds like your new wires are touching something they should not be touching

or you cracked a plug on the install

[Merlin]

I'll try replacing the coils and getting better wires.

[99W68Firebird]

when the misfiring comes back is it after the coil packs could come in contact with water? IE. Hard Rains / car wash. Cuz i have a leak in that cowl under my windshield and water leaks thru one of the lil screw thingys and goes thru the cowl and leaks right onto my coil packs every once in a while.

[Perry]

Originally posted by 99W68Firebird:
when the misfiring comes back is it after the coil packs could come in contact with water? IE. Hard Rains / car wash. Cuz i have a leak in that cowl under my windshield and water leaks thru one of the lil screw thingys and goes thru the cowl and leaks right onto my coil packs every once in a while.

I would replace that immediately, the weatherstripping that is.

[96firebirdgt]

it sounds like a vacum leak to me since i had the exact same problem.

check all of your bolts to the bottom intake and make sure they are tight since it is most likely pulling air from there.

having a big vacum leak or a bad pcv can cause misfires under hard acceleration or going up big hills where there is a big load on the engine

[cmartin99]

... it will eventually (prpabbly within a month or 2, get to where you can hardly drive it.. so i'd go ahead with some new wires and coil packs... you can get some good ciols and wires fror about 100 bucks

[99W68Firebird]

how often should u chance PCV valve and how much is it, where to order and how hard is it to change?

[96firebirdgt]

i paid $2.88 for the new pcv valve but you have to keep the spring from the old one.

i have dealer friends and they told me if they get a car having misfires they automatically chech the pcv valve

you can check it by unbolting the pcv plate and taking the valve out and blowing through the end with the spout if air comes out the other side then it is bad

you can get them at Advanced, Autozone, Pepboys,and a dealer

[jtblckmaro]

Check this out

http://web.camaross.com/forums/showthread.php?t=78028

[fenderman]

Originally posted by 96firebirdgt:
it sounds like a vacum leak to me since i had the exact same problem.

This is the problem with automobiles and "online" diagnosis. Problems unfortunately are not cut and dried. I can tell you that I also had this exact same problem with my Camaro and one of my coil pack terminals was corroded beyond belief. Replaced it and the car ran better. A few months later I experienced another misfire with no code but this seemed to be more at highway speeds. Nothing seemed unusual to me until I went to see about removing the air baffles (have a 99 3.8). The inner hose was not fully clamped at the bottom so from the top everything looked normal. This caused the hose under certain conditions to create a small gap which was just enough air to make the car hiccup. However under idle the hose sealed against the baffle making a naked eye inspection seem like everything was ok.

The exact same problem can have 3 or 4 if not more different solutions especially when it comes to automobiles. I am glad you suggested that though in an effort to help but I just wanted Merlin to know not to spend his whole time staring at vaccum hoses that may be very well sealed up and ignore other things that may be causing the car to act this way.

Merlin, what I would do first is start simple. As 96firebirdgt suggested check for vaccum leaks. I say this because checking for leaks doesn't involve pulling things apart. Simply check for any cracks, loose connections or a disconnection. If you don't hear anything while the car is running and the hood is up it may be a small crack (like dry rotting) or loose connection. If everything checks out with that then I would run a test on the wires and the coil packs. Remember with the coil packs to perform a test on both the primary and secondary terminals. Good luck.