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On my 97 bird... Those of you who visit the chat room may have heard me complaining about this before (my nick in there is kefkafloyd).
Okay... my car's been doing this dumb crap for a while now. I'm taking it to the mechanic tomorrow because I lack a scan tool to watch the engine.
First, when I start the car, the tach goes up to a bit less than 1.9K or so... but instead of going down quickly, it kind of sticks there (something in the engine makes a ticking noise as it goes down here) then goes down to 1.5k or so. Kinda jerky. I assume this is normal? this is unrelated, but I think my battery is on the way out too (dashboard's voltmeter reads the battery at just over the orange hashmarks when engine is off but key on, and I noticed when I started it the other day that when the engine turns over the voltmeter goes down then jumps up to 13 volts). Anyway...
Let's say you start driving. You'll be driving around for a short while... get up to 30 MPH or so and the tach is normally around 1.9K to 2K here. It seems at 30 MPH it does the following like clockwork: if you press the accelerator down slightly the engine feels like it's not getting enough fuel or something. The tach will fall from whatever it may be at to about... 1.6K or something, and pressing down on the accelerator further makes the engine accelerate very slowly until you get to a certain point when the power returns and the car is starting to go fast (this is generally above 2.5K RPM). You could accelerate very slowly into 30 MPH and just as soon as you pass 30 MPH it'll do this.
Now, let's say you don't press the accelerator in far enough... the tach will go up to say, 2.4K RPM, but then it'll fall right back down to 1.6K or so and climb slowly. This has been driving me nuts because I can't hold a constant speed, I have to accelerate fast, then coast, then go fast again, etc. At some point, this problem goes away, and car behaves normally.
Another funny thing is let's say you do a WOT run and let go of the accelerator, not easing off of it. Sometimes the car does what I like to call an "almost stall..." the tach will drop all the way down to 1000 RPM-ish, then the tach will quickly jump back up to the "rolling RPM." I think this is somehow an engine thing because I notice that the oil pressure dips down to the idle reading when this happens, but goes back up (the "working" pressure is around 60-ish, the idle pressure is around 25-30). Somehow I think these two issues are connected, even though the first issue can stop happening and the second one will happen on random WOT runs (I've been doing a few WOT runs everyday to see how many times this happens... sometimes it does, sometimes it doesn't).
Other tach funnies... sometimes when braking the tach will wobble around 1K.
It had a tune-up done in January (plugs, wires, coils, fuel, air, etc) oil changed recently (that time), transmission fluid changed and filter too, TPS and IAC sensors are also reasonably new. O2s were also replaced during tuneup. I had a new catalytic converter and driver's side exhaust manifold replaced under warranty. I also seafoamed it about a week ago. I have no SES light.
I'll see what the mechanic says tomorrow, but at this point I'm pinning it on EGR problems (that I can't diagnose without a scan tool) or exhaust leak (which I can't diagnose without a lift, and I don't have access). Anyone have any ideas?
EDIT: after doing some searching... I found this video, and I'll be damned, but it looks exactly like what my car does, except at 30 MPH or so...
http://members.cox.net/joshualabelle/RPM%20drop.MOV
[ April 20, 2004, 01:35 AM: Message edited by: Dan Vincent ]
Okay... my car's been doing this dumb crap for a while now. I'm taking it to the mechanic tomorrow because I lack a scan tool to watch the engine.
First, when I start the car, the tach goes up to a bit less than 1.9K or so... but instead of going down quickly, it kind of sticks there (something in the engine makes a ticking noise as it goes down here) then goes down to 1.5k or so. Kinda jerky. I assume this is normal? this is unrelated, but I think my battery is on the way out too (dashboard's voltmeter reads the battery at just over the orange hashmarks when engine is off but key on, and I noticed when I started it the other day that when the engine turns over the voltmeter goes down then jumps up to 13 volts). Anyway...
Let's say you start driving. You'll be driving around for a short while... get up to 30 MPH or so and the tach is normally around 1.9K to 2K here. It seems at 30 MPH it does the following like clockwork: if you press the accelerator down slightly the engine feels like it's not getting enough fuel or something. The tach will fall from whatever it may be at to about... 1.6K or something, and pressing down on the accelerator further makes the engine accelerate very slowly until you get to a certain point when the power returns and the car is starting to go fast (this is generally above 2.5K RPM). You could accelerate very slowly into 30 MPH and just as soon as you pass 30 MPH it'll do this.
Now, let's say you don't press the accelerator in far enough... the tach will go up to say, 2.4K RPM, but then it'll fall right back down to 1.6K or so and climb slowly. This has been driving me nuts because I can't hold a constant speed, I have to accelerate fast, then coast, then go fast again, etc. At some point, this problem goes away, and car behaves normally.
Another funny thing is let's say you do a WOT run and let go of the accelerator, not easing off of it. Sometimes the car does what I like to call an "almost stall..." the tach will drop all the way down to 1000 RPM-ish, then the tach will quickly jump back up to the "rolling RPM." I think this is somehow an engine thing because I notice that the oil pressure dips down to the idle reading when this happens, but goes back up (the "working" pressure is around 60-ish, the idle pressure is around 25-30). Somehow I think these two issues are connected, even though the first issue can stop happening and the second one will happen on random WOT runs (I've been doing a few WOT runs everyday to see how many times this happens... sometimes it does, sometimes it doesn't).
Other tach funnies... sometimes when braking the tach will wobble around 1K.
It had a tune-up done in January (plugs, wires, coils, fuel, air, etc) oil changed recently (that time), transmission fluid changed and filter too, TPS and IAC sensors are also reasonably new. O2s were also replaced during tuneup. I had a new catalytic converter and driver's side exhaust manifold replaced under warranty. I also seafoamed it about a week ago. I have no SES light.
I'll see what the mechanic says tomorrow, but at this point I'm pinning it on EGR problems (that I can't diagnose without a scan tool) or exhaust leak (which I can't diagnose without a lift, and I don't have access). Anyone have any ideas?
EDIT: after doing some searching... I found this video, and I'll be damned, but it looks exactly like what my car does, except at 30 MPH or so...
http://members.cox.net/joshualabelle/RPM%20drop.MOV
[ April 20, 2004, 01:35 AM: Message edited by: Dan Vincent ]
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