Rough acceleration

[fenderman]

Well, I searched the posts in this particular section of the forum, and found a lot of useful info. However, I wanted to see if there were any more opinions or if anyone with this problem found a solution.

I have a 1999 Camaro M5 3.8L. Under partial throttle, the car does not stutter (vibrate) but it is more like a violent hiccup. I'm going to try plugs and wires first to see if that does not solve the problem as it might possibly be a leaky wire, and then maybe the coil pack. All of these components look to be stock and the car has 56K on the clock.

My question is- are there any other ideas as to what this could be? I replaced the fuel filter and PCV valve when this first started to happen with no change. I also ran a few bottles of injector cleaner through the system as well. The car idles fine other than the occasional small shake, and it will cruise smoothly all day. Thanks for the help.

[Lon]

my car did the same thing. I mean exact same thing. some new plugs and wires and she is as good as new. with 89 thousand miles on her.

[jbfirebird]

could be wires, plugs, or even coils. dont forget injectors wether or not you put cleaner through them. i had mine manually cleaned because they were causing misfire. on the same tank of gas that i brought the car in for the issue, i was running injector cleaner in it. so it wont really matter wether or not you have put that stuff in, could still be injectors.

[AlienInv8r]

My car did that when I first got it, it was the plugs and wires that fixed it. Does it give you an SES light ever when this is happening? Mine started giving me a misfire code when it was stumbling really bad. Plugs are pretty cheap, you could try them first, and test the wires while you're at it. If they are the originals at 56k miles, then they're probably pretty due for changing.

[fenderman]

Thanks for the replies. All 3 of those comments help to solidify my guess as to what this problem is.

jbfirebird, where did you get your injectors cleaned? Even if the ignition components fix the problem, I'd like to have this kind of resource onhand for future reference as I maintain this car quite frequently to keep it dependable. I know injector cleaner doesn't guarantee anything, but I had never heard of a manual cleaning, only replacement. Knowing how expensive each injector is, I went for my only other known fix. However, I will add the manual cleaning option to that list.

AlienInv8r, there is no SES light coming on which is what makes this problem all the more frustrating. My guess is that this happens so infrequently that the computer dismisses it for some reason or another. The light does come on like it normally should when I first turn the ignition key, so I know that the bulb works. The computer just isn't registering this particular problem.

I will try the plugs and wires and see about the coil pack as well. Once again, thanks for the responses guys.

[ February 27, 2004, 02:38 PM: Message edited by: fenderman ]

[Ian]

mine is doing the same thing. no SES light, no codes scanned at all.

im ordering taylor wires in a few days, so we'll see if that works.

[Big Bad James]

Mine is a 97 and I'm having similar problems. I'm replacing the coils, wires, and plugs. MSD coils, Taylor 8mm SpiroPRO wires, and NGK Iridium plugs.

[jbfirebird]

when i had my car in the shop and found that the injector was causing the misfire they cleaned it there. just a mom and pop type of shop. basically any mech that knows what they are doing will be able to do it.
typically when injector cleaner is used it clears out what is inside of it but doesnt necesaarily clean any gunk on the outside of the outlet on it.

[AlienInv8r]

Mine didn't always give me an SES light either, I ran my car stumbling like that for probably almost a month before the light came on. It only finally came on when it stumbled really bad, and that's when I knew I couldnt put it off any longer. It made a huge difference with just the plugs/wires. I wouldnt get the coils just yet if I were you unless you wanna upgrade. A lot of times it will be just plugs/wires that fixes things, no need to spend all the money on coils if they aren't the problem. Troubleshoot a little and take it in steps so you can narrow down what it's specifically coming from. The most common cause for that though is the ignition stuff, It probably wouldnt be bad to check the injectors also though.

[RancidCamaro]

I've got a '99 as well, and I had the same problem - it was the spark plug wires.

[fenderman]

Had I not been lazy I would have just looked at the coil packs. I pulled off all 6 wires from the packs and the number 1 terminal looks like a chocolate raisinet. So, needless to say I'm going to be buying at least one new coil pack with a new set of wires and plugs. My question now is this:

GM wants 56 bucks apiece for their coil packs. MSD wants 40. Autozone wants 20 bucks but I am unsure of the brand so this is a last resort. I want to just replace all 3 with the MSD 8224 but I noticed that others here who run these packs have additional equipment. If I buy the MSD 8224 coil packs, will I need other MSD equipment or will these operate on the factory system? Also, if these coil packs operate on just the factory system, are they going to give me much advantage over the factory packs?

As far as the wires, I'm going with Taylor 8mm with plastic heat shields to eliminate conduction and for the plugs I'm going with Bosch platinums. I'll be placing my order on Monday so any other suggestions on a good ignition setup would be appreciated. Thanks guys!