Sometimes when I'm coming to a stop (10-0mph) my speedo will not reflect my actual speed. The needle dances through the speeds up to 60-70 mph while I'm sitting still.
Example:
0920001537.mp4 video by nanoman06 - Photobucket

After this has happened and when the light turns green or its my turn to go through the intersection the car feels like it is bogging (staying under 2k rpms longer than I'd expect), not as responsive as I would expect for a few seconds. After this happens sometimes the car jerks forwards (even if I'm not flooring it and I don't make a whole lotta power :sadface)

Seems to happen on both cold and warm starts. I can't figure out how to replicate the issue but if you drive the car in a stop-and-go setting like a town you will definitely experience this soon or later.

I have noticed one other thing on the way home with my cruise control on. For most of the miles home with it on it was functioning normally. I think it happened once, where on a flat strip of road, no bumps nothing to slow me down I noticed the car rev'd by itself to 3.1k. For the speed I was going I only need about 2.5. Seems like while the car was on CC it slowed down or the CC stopped working for a few seconds then kicked back in. This seemed strange to me so I figured I'd add this in.

I have no malfunction / check engine lights on. I used seafoam and cleaned the TB about two months ago (4,000) miles ago. I'm at 582xx miles now. Anybody run into this? Over the weekend I might try new plugs and fuel filter but would those also be the cause of the speedo acting weird?

 

oh chevy and your notorious speedo issues... this is an issue with so many gm cars... the clusters just stop working... i never did find out why... the tach in my moms suburban says she is at -250 rpms at idle.... i guess her engine turns backwards till she gets moving lol... but if you google chevy og gm speedometer issues you will find this all over the place.

 

Definately possible, do you think that could be the issue behind the bogging as well?

 

not so much... clean your tb and all your intake parts.

 

I'm going to assume you're an auto trans, check all your fluids, and sensors, then have someone who can pull error codes check it out.

 

time to flush your ENTIRE CAR... get a fuel system cleaning service done

 

I'm a human being dammit! I have an auto trans in my car yes
I don't see any CEL on but is it possible for there to be error codes without that on? Ill try to check in with a neighbor, he might have access to a tech II.

 

Does your cel light up when you start your car? (damn light bulb is out you wont be able to see it, fussy things)

 

It lights up with the other lights like it is supposed to when the car starts up and turns off after that period like the rest of them so, I would assume it's working correctly and I don't have any codes.

 

Then i'd check fluids, maf sensor, coilovers and plugs. somewhat random when was the last time you cleaned your air filter?

 

just realized i typed coilovers, not coil packs...

 

lol I knew what you meant lol

 

Yeah dude, that's harsh. I'm having issues, as we discussed, but not that phantom speedo.. But I did replace my 2.4 white-faced one with a black SS s/c 160 one..

 

The bogging issue could be a TPS sensor I saw something similar happen on a L61 Malibu. The TPS voltage would suddenly fluctuate causing the RPM to jump during cruise then when hot the TPS would be very slow to react causing a bog.

 

Hmm, interesting. It's at the dealer now. Hopefully its nothing expensive...lol.

BTW, are you the guy who used to run ef?

 

Sorry can't say I am. I am on there but never ran it, That would be NJHK.

 

Nooblar, for whatever it's worth, I super duper cleaned my TB and my MAF yesterday and it seemed to help alot with my poor reaction.. I'd check it out. But definitely keep us updated.

 

Got the car back! The wiring to the speed sensor needed to be replaced.

 

So that fixed the random speedo action? How about the bogging and such?

 

It fixed all of the issues I had actually. I thoroughly tested it today...haha. I got the PS recall done to (even though I didn't think I needed it) and it seems easier to steer now, guess I did need it.

 

Hmm, so what exactly did they replace/do?

 

"Vehicle speed sensor harness is shorting to ground R&R harness replace 6-10 inches of harness and reroute to clear engine."

 

haha Gotta love tech's explanations..