bad missfire
 

so i finally finished painting the firebird take it for a drive and realize it has developed a bad misfire. it was time for new plugs/wires. So i swapped these out, but the problem wasn't effected. The misfire happens only when the car is in gear and im trying to accelerate. also i think its a random misfire. i suspect it might be vacuum leak. what else could it be

6cyl. or 8cyl. ???? if its the 6cyl. its most likely 1 of the coil packs, very common to go bad. usually will idle fine but once on a load stutters/misfires

2nd. coil usually one to go because its sandwiched between the other 2 and gets the most heat

ya its the 3.4. do i have to replace the whole thing or just some bits and how can i double check this

so my friend had an obd computer and he pulled the codes for me and sadly i had a bunch
1) 75 EGR solenoid
2)76 EGR solenoid
3) 77 EGR solenoid
4)36 IC 24x signal error
5)22 throttle position sensor too low
6)82 ignition control 3x signal error

does anyone know what any of these actually mean and how i should go about fixin it

pull th egr out and look and see if there is a piece of carbon holing the valve open. that will cause those codes and it to run rough/miss
take a pick and pop the carbon out if it is in there, put back, then should be fine

bad EGR valve?

where is the egr gonna be and what does it look like

its on the passenger side of the intake manifold. it looks hilarious and runs from the exhaust manifold to the intake manifold. its tough to miss. spray the bolts with a rust penetrant and have at it.

I see alot of 3.4 have EGR problems. just replace and go from there.

well i cleaned out the EGR with a wire brush and then used brake clean and let it air out. seems to have fixed the problem for now. hopefully i wont have another hiccup

3.4's with throw those egr codes regardless if the things is brand new or old as dirt. Any time I decerlerate and coast that code gets thrown and ive spoken with several 3.4 owners whom all have the same problem. doubt its you egr.

I had everyone of those codes, same exact ones, thrown at the same time a few months back. started replacing everything from egr, tps, all three coils, plugs, wires, iac, 24 and 3x sensors, seafoamed it and cleaned tb, and a few other things and was still haveing a horrible missfire so bad it would stall under load, and got worth when the car got hot - even got hot quicker than normal just in park in my driveway.

Took it to two different places cause I was stumped. Some thought I had a vac leak but smoke test showed nothing. One guy thought i had my egr on backwards, idiot. Ended up being a clogged cat for me. Here's the funny thing though that cat looked great when they cut it out and my exhaust guy looked at me a laughed saying he told me so. but when he put the new on in and we went for a ride - it was perfect no missfire, no stalling out. nota.

not saying thats your problem but that was my trouble with my little 3.4

ive actually read about the clogged cat being the problem. i was thinking about just hollowing the damn thing out.would this fix the problem?

i dont think that will fix anything... except cost you money when you need a new one to pass inspection, or it will make you throw an o2 code

my buddy did that to his truck... no o2 code because his post cat o2 sensor was tuned out when he got his truck tuned

the only O2's we have are on the headers before the cat so no prob with that. I have a cutout right after the cat and I had alomost nothing coming out of the pipe, very little pressure.

If u hollow it out and it rus fine then thats your problem. If not u f'ed up an ok cat. You can pick up a carsound/magnaflow high flow for 65 bucks if ur out of ideas though.

why not just take a look inside the cat....if theres chunks of honeycomb all clogged up in there take a broomstick and bang it out....if it looks good then it probably is.




get a volt meter and test the ohms on the coil packs should read between 5-7 with a decimal point somewhere there....

ok so i took apart the EGR and cleaned it out with a wire brush and then sprayed it with brake clean and it seems to have solved the problem. but its still running a bit funky so im gonna clean out the cat and check the coil pack when i get a chance

How old are the o2's?

no idea. ive had the car for a year and i havent changed them

do u have anyway to scan ur car for real time information? i had an o2 act up one time and it was causing problems.

nope. why do u think its the 02?

cause if one or both are bad they can really make a car run like ****