nighthawk15

Ok, some of this is a little hard to describe, so bear with me. Since last year my car seems to have a bit of a miss right around 1500 RPM and below. Basically as low as you can go without lugging the hell out of the engine. At idle you can also sometimes feel the car run just a little bit rough, but nothing too pronounced. Here are the two parts that confuse me.

1.) it seems throttle dependent. For example if I am in 6th gear at 55-60 and give more than about half throttle it seems like I feel a minor miss every now and then, but if I only give it light throttle, I feel nothing of the sort. I am definitely not mistaking lugging for a miss as I have had this car since 06.

2.) I can be anywhere else in the rev range, with any amount of throttle, even WOT at 6k, and the car runs beautifully.

I do know I have a vacuum leak because air only blows out of my defogger and foot vents. Would that be the likely cause of what I'm describing or does it sound more like the opti going bad? If it makes any difference my idle is the same as it has always been.

lemons12

iTrader: (71)

I would check plugs and wires.. probably not the problem but one of first things I always check.

nighthawk15

Found the issue with the vents. a hose got knocked off the check valve. I have my doubts that was the issue with the miss, but im about to go drive the car anyway so we'll see.

nighthawk15

And that vaccum leak was definitely not the issue.

nighthawk15

Now throwing a p0300. thoughts?

lemons12

iTrader: (71)

Did u ever check plugs and wires..

nighthawk15

I will probably check all the plugs and wires this weekend. Would that be likely to cause such an isolated issue though? The miss is only under low rpm/heavy load conditions.

lemons12

iTrader: (71)

Yes.. Plus it is simple and cheap to replace.

96TransAmboosted

iTrader: (8)

300 code is a random miss code. could be a plug that is wet,oil soaked ect. or a wire issue. the best way to check for a miss is to brake torq the car up slow to 1500rpm or so. you will feel it if its missing on the low end most of the time this way. The plugs can just be pulled and checked the wires are a bit more to check over and examine them since they are tucked away pretty good.

lemons12

iTrader: (71)

this. I have been on phone so not typing a lot lol

I would buy new plugs first see if that fixes it.. cheap probably needs to be done anyway and fairly simple. After that check plugs

nighthawk15

Thanks for the input. My wires are actually OTVC and I have pretty easy access to all my plugs and wires, so I'll check them all probably this Sunday since I'm busy all day tomorrow and Saturday. The plugs have a bit over 10k on them so I'll just go ahead and get new ones since it will be basically the exact same amount of work. The wires were changed at the same time and have book protectors on the ends, but I will for sure check all my wires to make sure all my terminals are good and no burns anywhere.

EDIT: On second thought, it appears I'll have a couple hours before work tomorrow and the NAPA right by my house has them. So I'll probably be able to report back tomorrow.