For the last couple weeks, my car has been chugging a bit at lower engine speeds, NOT while accelerating or decelerating, but while attempting to maintain speed, like behind a slower-moving car. It is more noticeable at lower RPM's, and is also more noticeable when just starting off when the engine is cold.

Idle is good, but not PERFECTLY smooth, like it normally is. I replaced the O2 sensor, but it didn't seem to make a difference. All of the normal tune-up items are OK.

What next? TPS?

 

Timing ok?

K/S maybe?

Driver maybe?

 

Do you have a Fidanza? I didn't see it listed in your mods.

Mine seems to "chug" a bit when going about 20-25 mph if I try to maintain a steady speed, even in 2nd.

 

We already know what your problem is though..(*cough* he needs a caw*cough*)

 

take the TPS off, open it, clean the contacts and see if that helps.
also make sure all the linkages for the throttle are moving freely.
it could also be that you have a shaky foot

 

I don't have a shaky foot, nor to I have a Fidanza.

Knock Sensor, eh? Maybe I will check that out.

 

will the TPS cause problems going up hills? I can floor it and it has a hard time climbing and reaching speed.

 

mine just threw a code 34 which I think is the knock sensor. Will it cause a chug like he is describing? I know its not the injectors. Let me know what you find.

 

Yea, it's the k/s i can't find the harness on my v-6 3000

 

 

Mine did (does) that before the cel came on and it felt like a cylinder wasn't firing. The cel actually turned off and the issue went away but I can still feel that chugging slightly. I'm going to try to get the codes, I never knew the ecu had leds for this.

 

Thanks for the diagram MygreenMax, i got codes for k/s and o2 so when I get those changed i'll report back.

 

I haven't tripped the check engine light, so I don't think it's the knock sensor...

 

Mine never tripped the check engine light but i check the codes and will be replacing it on friday. Right now it has a slight miss and has a hard time accelerating up hills. One I replace the knock sensor and O2 sensor I will let you know if i get my full power back.

 

Check your codes anyway,sometimes the ecu will store a trouble code without a cel warning.

My k/s never tripped the cel,but the code was stored when i checked my ecu.

 

OK, I've now got a better way of describing my problem. I started the car today and played with the idle. With a light, steady input on the throttle the engine speed increases, but stumbles as it does so as well as when maintaining the higher idle speed. When revved, there is no stumbling or stuttering. Symptoms are much less noticeable when car is warm.

 

stop using 87 octane (only use 93 now), run some injector cleaner in youry gas, do an oil change.

if you're just getting hesitation, all of the above may help you. i had that issue when i started delivering pizza in my gxe (how stupid i was), but after all of the above, i never had it again, even after the 50k miles in 3 years (bought the car at 144k).

i had another similar issue and it was way worse; it happened while i was in the process of installing headers/replacing header bolts and i was driving around without any exhaust manifolds. my car was shaking very badly after going from park to drive and low speeds. i changed the oil and the issue stopped immediately. the oil smelled like firecrackers. i then changed it again, just to be safe, a few days later. i also got the exhaust fixed and never saw the issue again.

 

No offense, but don't talk to me like a newbie...I alternate tanks of 89 & 93, injector cleaner sucks, and I change my oil frequently and often...

I am merely searching for someone with experience mentioning something profound I may have overlooked...Typical tune-up items are obviously not the cause, as I have mentioned before...

 

You change your oil frequently AND often?! Hot Dawg!

 

Yes sir!!!

 

Well, guys...today my problem manifested itself as another injector sh!tting out on me...I replaced the one on cylinder 4 about a month ago in case you didn't know. I used a mechanic's s***hoscope once again and it appears to be cylinder 2 this time...the only one you can't get to to pull the wiring harness and confirm it.

I suppose I will be ordering 2 injectors and have a whole new front fuel rail...and pray that none of the back ones go anytime soon...

 

Well, I just ordered 2 new injectors from Brian...hopefully they will arrive by this weekend so I can install them...

 

My car did this but it ended up being a vacuum hose was unpluged. It's the one on the backleft corner of the intake. I wouldn't have noticed if an another fellow mechanic didn't point it out.

 

Making sure there are no vacuum leaks is important...I replaced all of the worn-out ones last month when I had the intake plenum off to replace the first injector that went bad...It's a lot of fun figuring out where they all go when you put it back together!

 

Well, I'm going to post-***** my own thread for a minute...2,000 posts, bishes!!!

Now, a relevant question: has anyone else dumped fuel over a new injector before installing it as an alternative to putting lube on the o-rings? It worked fine for me last time...