The situation is simple to reproduce and I've tested it multiple times this way. On the highway at 35-40mph in 3rd gear (around 3000rpm) and I go WOT. The car accelerates but has a very apparent "miss" or shudder. If I go 70-80% throttle, the car will roll on just fine. This happens with a warm engine and I started noticing it after a longer cruise I took a few days ago. The car has 117k miles on it and is due for an oil change (a little past due, actually), but everything else is working fantastically. I'm not throwing any codes out of the ordinary, besides the P0420 Cat code which crops up from time to time and I clear. I've also been sticking to the same Super America 87 octane gas for a few months now, so I don't think it's a bout of bad gas. I heard from a buddy of mine that it might be as simple as moisture on the coilpack. I was also thinking it might be sparkplugs. However, I don't think either of these are the issue - the miss happens at high RPM whereas sparkplugs would normally happen at low, correct? And there's no moisture on the engine as it hasn't rained or snowed here in a while. My other consideration is fuel delivery. Could this instead be an issue with the fuel pump, fuel filter, fuel rail or injectors? And if so, what are some common maintenance options to cleaning or servicing these items? I have the full service manual in PDF and would read up on or ask for help with any of this stuff, but I'd prefer to do it myself to get a better understanding of it - if it's not too hard. If there's anything any of you can think of checking, please let me know. I love this car and miss being able to tromp on it without it crying at me.
I actually just had the same problem with my car the past few days, and the guys on here told me it's the knock sensor, so test that and see what you come up with. I replaced mine, and the problem cleared right up. just a thought
you probably need new plugs and wires, and or coil pack, or vavle cover ring seals, when they leak it makes it miss under load, lindsay138 had the same problem in her rs
Hmm, okay. I'll take a look at the knock sensor, and was thinking I should probably do the plugs and wires anyways since I don't know when they were last done. I've driven the car about 18k miles since I bought it. While I'm at it maybe I'll just take care of the coil pack too. Thanks for the tips, guys.
Also try a tank of 89-90 octane. That might lead you one way or the other if it is fuel or timing. You could also just run a tank of 92 and that will do the same thing. Russ
My old RS stuttered on the freeway under wot when my clutch was just about dead. Might be something to look at.
Actually YES CUP...if the rpms are going up and the car isn't going anywhere that is a symptom of dying clutch.
nice job pete you are right! but a slipping clutch is not "missing" or hesitating...a miss would be a huge jerk at a certain rpm
OP described it as miss OR shudder and when that happened in my RS you could qualify that as a pretty damn big shudder :biggrin: whatever we can stop cluttering this dudes thread. If the plugs and wires don't fix it its worth a check. All I'm sayin.
Yeah, I've wondered about the clutch since I bought the car with 99k on it, but it's worked like a champ so far. I'm really comfortable with this gearbox and I rev-match when down-shifting. I don't beat it up and it's never given me any problems. I don't know how long the first clutch is expected to last on the car but I was under the assumption that the clutch has already been replaced once. Either way, it's another possibility and a good thing to take a look at if the plugs don't do it.
Does it only do it when warm(engine)? Are there any symptoms under partial throttle? 30%, 50%, 80% whatever...
Mine died in my 01 RS at about 137k IIRC. More than likely if its just a miss its probably plugs/electrical or fuel. If that doesn't work its an avenue to explore.
I haven't had a chance to try it on a cold engine simply because I try not to drive like that when the engine is cold. However, as I stated in my original post, as long as I'm not WOT, the engine just goes fine. Maybe I'm just not noticing the miss simply because it's not WOT so the miss is smaller. I have more and more of a feeling that it's the plugs and wires, as that was my first gut instinct given what the engine was doing.
Well, I tested it on a cold engine and warm today and neither gave me the issue. I'll keep the ideas you all gave me in mind and will keep my eye on it. Thanks again.
your clutch is probably going, mine did the same thing when mine was about to go. it slips and grabs and slips which causes the shuddering. my stocker last me 109k.
Hmmm, well, I'd hope it's not that but if it is, hey new clutch. If it's that, where should I look for a good replacement, one that I'll appreciate? And how difficult of an install is it? As I said earlier, I'd love to be able to do this kind of work myself, and now that I have a nice garage for it, I'm excited to do it.
I'm bumping this as a follow-up. I did my plugs today and that did the trick. She's back to her old self and I love it. You're right here - I do need to do my valve cover ring seals next. I pulled the first boot and got a little spray of oil following it, as did all the rest of the boots. Not much, but it's there. The boots were in very good shape so I'm not going to do it right away, but it's definitely on the to-do list! Funny thing - this actually triggered a CEL today for the first time ever. I'm going to keep an eye on it and if it keeps popping up (didn't at all during my test drive) I'll look at replacing it as well.
