Rough Idle with AC - Hesitant acceleration - Exhaust Rattle
#1
Rough Idle with AC - Hesitant acceleration - Exhaust Rattle
Hey guys, I drive a 2000 Chevy Blazer with 219k miles. 4.3 liter 4x4 4 door.
I can't figure out what these issues are to save me life:
1&2) I have a really rough idle but only when I have the A/C on. When I come to a stop light, my car starts shaking pretty bad if I have the A/C on (cold) but if I turn it off, it's completely fine and idles smoothly. However, when I go to accelerate from stop, it has "choppy" acceleration as if it's struggling. But once it shifts up once or twice, it's fine. It's even worse if I accelerate from a stop WITH the air conditioning on. I am almost in need of an oil change but it did this even the last time I had it changed. I have read around that the shaking may be coming from the IAC valve and that I need to clean it. I'm going to try that soon but I am curious if there are any other suggestions. It's probably due for a tune-up (plugs and cables) and that is on my list, too.
2) I can hear a rattle/high frequency grinding sound that changes frequencies and noise when I am accelerating, which gear I'm in, etc.. I had my muffler replaced (had a hole in it which I thought was the problem) and the heat shield on my Catalytic Converter re-welded (was half hanging off) but the problem is still there. I haven't been able to pin-point where the noise is coming from specifically.
Any help would be great!! Thanks so much.
I can't figure out what these issues are to save me life:
1&2) I have a really rough idle but only when I have the A/C on. When I come to a stop light, my car starts shaking pretty bad if I have the A/C on (cold) but if I turn it off, it's completely fine and idles smoothly. However, when I go to accelerate from stop, it has "choppy" acceleration as if it's struggling. But once it shifts up once or twice, it's fine. It's even worse if I accelerate from a stop WITH the air conditioning on. I am almost in need of an oil change but it did this even the last time I had it changed. I have read around that the shaking may be coming from the IAC valve and that I need to clean it. I'm going to try that soon but I am curious if there are any other suggestions. It's probably due for a tune-up (plugs and cables) and that is on my list, too.
2) I can hear a rattle/high frequency grinding sound that changes frequencies and noise when I am accelerating, which gear I'm in, etc.. I had my muffler replaced (had a hole in it which I thought was the problem) and the heat shield on my Catalytic Converter re-welded (was half hanging off) but the problem is still there. I haven't been able to pin-point where the noise is coming from specifically.
Any help would be great!! Thanks so much.
#2
Yes, pull the iac sensor and clean it!!!! also do not cheap out on tune up parts!!!!! acdelco all the way ! Cap,rotor,plugs and wires.....u can use autolite professional wires as a cheaper alternative if u use any other brands u are asking for problems.......... as far as exhaust rattles, well I just pull the heat shields off when they start to rattle
#3
Yes, pull the iac sensor and clean it!!!! also do not cheap out on tune up parts!!!!! acdelco all the way ! Cap,rotor,plugs and wires.....u can use autolite professional wires as a cheaper alternative if u use any other brands u are asking for problems.......... as far as exhaust rattles, well I just pull the heat shields off when they start to rattle
I definitely don't plan to cheap out! (except i just got a reman'd alternator because I was tired of the squealing in the pulley) and haha. pretty sure it's not a heat shield though. Definitely sounds like something internal.. but when i clean the iac and replace the other stuff i will definitely update if the problem is still here or not. and as far as the exhaust noise, I still am clueless but will be a little more diligent in trying to be more specific
Last edited by AlexS; 09-21-2014 at 06:37 PM. Reason: extra details
#5
So the exhaust rattle was because my cat heat shield was resting on the cat. Pulled that back with about 7 mm clearance and noise is gone completely. More info on the violent shaking sluggish acceleration from stop: it may also be my tps sensor. If the IAC valve cleaning doesn't help, I'm gonna replace distributor cap and rotary button, then tps sensor. I'll keep updated.
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ubrainium
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01-02-2012 06:39 PM