Missing, stumbling under load ?- replace plugs & fuel filter - HELP!!!

[Hugger3800]

Ok I have 60K on my 99 and out of no where it has started to stumble like its missing when excelerating or under load. It stumbles more when its hot than when its cold. Won't do it all the time just when it wants. I replaced the plugs which all still looked good and the fuel filter again after 15K miles. Is it wires, coil or something worse? Also I have never got a SES light on my car in since I've owned it.

[John D.]

Could be both, wires and coils. I would check the wires first just because their easier. I am leaning towards the coils though because it gets worse as the car warms up.

[Hugger3800]

I should have asked you all before I replaced the plugs b/c they still looked good plus new ones are $$ but oh well. Where is the best place to buy a coil and how much do they run?

[andrew.brandon]

Same thing happened to my car. I changed the plugs and wires and have a filter sitting in my room waiting to be put in. The wires and plugs change out stopped the sputtering but now the engine sounds a little different. I don't know what is going on.

http://www.camarov6.com/cgi-bin/ulti...c&f=1&t=011661

See if that helps, those are the responses I got.

[ February 04, 2004: Message edited by: andrew.brandon ]</p>

[Pewter99Camaro]

Your best bet before you do anything is to remember back and think about weather or not you dropped any plugs-cracked porcelain, next go back 1 by 1 and regap the plugs. Mine did the same thing and it was back to normal after I went back and regapped the plugs.

[mcG]

i changed the plugs, wires, coils, maf sensor, and still have the misfire. it also stutters when i accelerate for a bit before it downshifts. when it gets warmer im gonna re-do the plugs and wires at the same time and go from there.

[Hugger3800]

This occured before I put the plugs in and the plugs came pregaped(expensive GM factory 100K mile replacements) I think its probably the coil because it has a hard time starting sometimes when its hot - just a guess but for $30 its worth a test - I'll also do wires at the same time.

[andrew.brandon]

<blockquote>quote:</font><hr> The wires and plugs change out stopped the sputtering but now the engine sounds a little different. <hr></blockquote>

Don't bother with this info, I found out yesterday I have an exaust leak. I guess that would do it.

[Die Ford V8]

before spending your money on wires, plugs, and things like that, look at every possible thing and make a list, then do the "process of elimination" read more posts but if i was you Id get it checked by a computer. a computer will tell you what cylinder is misfiring. that right there is a huge step. might make a lil misfire but if you changed them once and they are gapped, cross that off of your list. for wires, go rksport. those gave me some hp and better mileage. my car hit 115,000 before i changed my plugs. i got the car at used so i thought they would have been changed allready. then i found out they were 100,000 mile til tuneup cars. the feul filter wouldn't do it. if it seems you are running out of gas, and you wait a little and your full again then yes, just get your computer checked. check your wires with an om* meter or look under your hood when its pitch black and look for arcing. it might even be o2 sensors, exhaust leak, it might, it might, it might, whatever. check for the obvious then start with the harder.

main thing: get the computer checked, focus on what cylinder is not firing, ask for PROFESSIONAL ADVICE, and do some cheap troubleshooting. if its only one cylinder to focus on there isnt much more than a plug, a wire, a coil pack,or a computer. maybe compression but i doubt it. be smart and dont waist valuable time and money. Good luck man.

[jayxer]

Ok, I have the 3.4L L32 V6 in my 93' Camaro. It idles perfectly, but when you step on the throttle, it bogs for just a millisecond. It runs fine all the way up to redline. It just seems to bog down a little at first. Has anyone else's done that? If not could it be a injector problem?

[y87inside]

Hugger it could be a # of things and id be willing to bet its not your coils. If I were you id pay the little bit of $ to have it taken to a reputable shop a put on a scan tool or vantage. Lots of things can cause your problems, even something as unlikely as a engine coolant temp sensor or a map sensor thats acting up. Sometimes these will not throw codes untill they go way south. Check to make sure all the vacum lines are connected also. Even though this would cause a stumble at idle as well even while its cold, id still check it out. just some personal advice from expierence. Good luck!

Brandon