Now it is Stumbling a cruising speeds?

[97firebird3.8]

Okay the background: Had misfire fixed with coil pack change and new plugs and wires. No misfire but Stumbling now occurs. Checked wires and plugs (only 3 weeks old on both) all still good and no burnt plug wires. They have been routed around and away from manifolds. Got codes check and it said Multiple misfire on multiple cylinders and EGR code. Changed EGR and all was 100% better. New fuel filter as well. Well last few days now bogs or stumbles at cruising speed only with no misfire on the SES also if you give it a little gas the stumbling stops and it takes off. New fuel filter as well. I am getting fairly annoyed with this. I know I am not the only one with these problems.

Possible fixes?? Or places to look other than plugs, wires, EGR and fuel filter? The multiple misfires on multiple cylinders makes me think maybe ignition module? But like I said no SES misfire light just the stumbling at cruising speed. No stumbling at throttling.

I am lost now. HELP!!

[97firebird3.8]

Sorry this is a 3.8 in case anyone was wondering.

[95Batmobile]

I am having the sort of the same problem with my car.. missing and backfiring when I take off..
Here is what could be wrong with mine:
wire, coils, plugs, ignition module, maybe my DIS-4 messed up. I think those 4 were it.. mine is most likely wires tho, since one is burned up.

I don't think those ignition modules are cheap either.. but that does seem like the source of your problem now.

[Turbo V6 Camaro]

did you put fuel filter in the right direction sound like it starving for gas ???

[97firebird3.8]

no filter is on the right way. It has two diferent sized ends so you couldn't wrong. It only stumbles on cruise not at take-off

[Speed Freak]

I Had the same problem,(random misfire)
it turned out to be a cloged cat.
free fix at the dealer if your under 75k mi.

[99W68Firebird]

yea im having that problem right now.. thought it was just some bad gas... or not enough octane because i have the jet chip and accidently put in mid-grade.. but the past week i went to 3 gas stations that have been good and never had that problem with gas and car is running bad again sounds like same thing that 97firebird3.8 is having i just dont know what to do to fix it..

[hawgs]

I had this problem. Was getting a misfire on all cyl. on the drivers side. Coils didnt help and plug wires were fine. I checked the PCM terminals and there was corrision inside there. Cleaned it off and it runs great. I had washed down my engine the week before and apparently gotten that wet. Just a thought..

[97firebird3.8]

I am lost on this one. Cat seems to be fine. Not sure on the pcm. ANy other ideas?

[mcgs999]

EGR fixed? is it the valve of the whole system? Also what about injectors? Are they clogged or bad? I am drunk but i think i am right!

[Smitty]

You might want to check for a vacuum leak in a vacuum line....That to would also cause a stumble at crusing.
Also you might try upgrading to a better coil...I had that same problem i went to MSD coils and Performance wires and everything is just fine.

[vampyr]

you stated that you changed a coil pack did you change just one or all 3? I had 2 go bad on me in like a month and both times the PCM was reading multipul misfire. just a thought...

[97firebird3.8]

Nope just one. Tested the others and they were fine. This feels different than a coil pack misfire. I have had that many times. No cash to upgrade to the more expensive ones. Just need it running right to get where I need to go. Going to school right now so cash is a major problem.