jlashley2001ss

iTrader: (5)

let me explain what is going on with my car. When i come to a complete stop my car seems ok. When i let off the brake slightly my car seems to fludder, skip, hesitate, whatever u wanna call it. When i cut the A/C on my car doesnt do it!!! What u guys think it could be?? Im so confused and bothered by this!!!!!!!

BTW i just changed my wires and plugs about 200 miles ago so its not that TRuST ME!! ive went back and checked my wires and none of them are burnt. my car is an 98 z28 A4 w/3.23 about 53,000 miles on her!!!

NoGo

iTrader: (2)

It sounds like your car is having idle problems under load. Cammed vehicles usually experience these problems. Are you stock?

When you turn your AC on, the idle is kicked up a bit which alleviates this problem.

If you are stock (ie have the stock cam) then I would first look at the MAF. Is there any goop on your resistors?

Some stock vehicles in the higher mileage have had problems with carbon build-up in their cylinders. Several people have had idle problems because of excessive carbon buildup. This may be something to check as well.

And last but not least, the poor mans guide to what went wrong: Just ask yourself the question "What in the hell did I change right before I started to get this problem". If the answer to this question is your sparkplugs and wires, then yes, you should check them again. Are all of your sparkplugs gapped properly? Are all of your wires within the rated resistance (should say on the box)? Are all of the sparkplugs sparking?

Good Luck
<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

jlashley2001ss

iTrader: (5)

my internal parts are all stock!! i put in ngk-tr55 plugs and after about a couple thousand miles on the plugs and wires the problem started! so then i installed the bosch plat. +4 plugs, which u do not gap, and the problem is still there.

what u think guys??

jimmyblue

iTrader: (11)

If it does this once, every time you release
the brake, that could be a vac booster gone
leaky (or signaling another vacuum leak,
that makes the motor indicate when any more
leaning-out occurs). Then again, it could be
just load release on the motor. The way to
check this is to jam the parking brake on
enough to stop you from creeping, then hit the
main brake and release. If engine shudder does
show every time, then it has to be the vac
booster. If it only happens when you release
the parking brake, then it's load release.

Vac booster may be the problem, or just the last
straw. The recharging air pulse makes a lean
transient that the motor may react to, if it's
already lean enough. This transient is a bigger
piece of the total airflow when the engine is
idling low, without the IAC jacking it open
(like when A/C is engaged).

Is your idle just generally low? Mine gets down
below 500 (indicated) when hot and loaded. A
little bump-up might be all you need.

PontiacMan7901

guys, the noise is ameliorated by cutting the power to the AC. what it sounds like to me is a bad alternator because the AC drains tons of power from both the engine and the battery. the alternator sounds like it's only partially charging at idle speeds and the reason it doesn't happen at speed is because the alternators charge in volts is increased by the engines rpm. just check the alternator buddy <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

wrencher

iTrader: (2)

A/C off it doesn't do it? Is the a/c clutch cycling on/off constantly when a/c is on? you may have a low refrigerant charge in your a/c system .

nthnwbr

My advise to you would be...take out those Bosch plugs and throw them in the trash. Even if this is not the problem now, they will cause problems in the future. I have seen Bosch plugs do every thing from cause misfires(even though they appear to be ok) to just plain FALLING APART INSIDE THE ENGINE. I worked in a shop that had a steady flow of do-it-yourself people come in to have us fix their foul-ups, and 95% of the time that we found an ignition problem, it was due to Bosch plugs.

pbperformance

we installed bosch 4's in a 5.3L and the damn wouldn't even start. reinstalled factory plugs ac/delco ......... ran like a champ.

sited12

I had the same exact problem. And when i started it up and let it idle for about 5 mins it would die. It was the EGR valve. So get that checked out.

jlashley2001ss

iTrader: (5)

u think it may be the egr valve??

01Z0H6

iTrader: (63)

Bosch plugs!! There is your culprit!! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

jlashley2001ss

iTrader: (5)

u think it might be the alternator??

jlashley2001ss

iTrader: (5)

i had ngk tr55 and it was doing the same thing. I changed to bosch plugs thinking it might have been the ngk's but my car still doing the same thing. so its not the plugs.

TomQ

how many amps is the stock alternator for 2k1 f-bodies?

BrianLS1

I'm voting alternator..good luck.

01 SS Jay

I may be way off base, but why dont you go ahead and do an idle relearn re-quick and eliminate that. I had to do one for just changing the air filter two weeks ago. Damn thing wouldnt idle for **** until i did a relearn. Strange stuff.