Couple of issues, engine and manual transmission

engines
pontiac
vibe
transmissions
matrix

#1

I bought a 2005 Pontiac Vibe about 5 months ago. It’s got a manual transmission. It’d been several years since I’ve driven a stick (last manual owned was an '85 Honda Civic DX), so I was reluctant to blame the car initially for things that I thought seemed wrong. It’s still under a GM Certified warranty. 5 months later, I’m not sure there aren’t issues with the car…



1) I noticed that there were times that, when “cold”, the engine would go from between 1000 RPM and ~2500 RPM, cycling again and again and… The dealer said “we can’t reproduce it, there’s nothing wrong, let it warm up totally before driving”. I’ve now determined that this happens when: a) the engine hasn’t warmed up entirely b) and the car’s moving c) and not in gear (I pull out and am coasting). This isn’t right, is it?!?



2) Also related to engine idle… I swear, sometimes it’s idling as low as 700 RPM (as much as you can trust the analog tach), but typically just under 1000. Sometimes, it stalls VERY easily (I don’t think I suck THAT much, still). And, sometimes after it’s warmed up, and I’ve pulled off of an interstate exit ramp or some such, it idles at 1500-1700 RPM’s for >= the length of a traffic signal. Again, dealer dismissed this :frowning:



3) It grinds going into reverse ~10% of the time?!? The dealer said “yeah, we reproduced that, typically on a slight incline, that’s normal”. That sounds like B.S. to me. Am I right or are they?



Will all the hubbub about Toyota, I’m now especially conscious of this stuff. Can you offer any guidance? Or am I the idiot the dealer made me feel like


#2

Sorry, P.S. it’s got ~53,000 miles, for whatever that’s worth…


#3

I own 2 Toyotas, both manual trans. They do not have syncronizers for the reverse gear. I found the best way to shift smooth into reverse is to shift into first, then reverse. This uses the first gear syncronizer to help get the gears to line up better.

As far as the higher RPMS coming off the ramp and cycling when cold, maybe a thorough throttle body cleaning can cure this. I question why your coasting out of gear, as this is typically a no-no, especially coming down a steep incline or hill.


#4

Thanks for the quick reply!

Will try the first/reverse thing (might have tried it early on? Don’t remember, certainly worth another go).

Coasting out of gear, is if I’m low speed approaching a stop after having just started out from another… city driving with stop signs every block for a couple of blocks. How long might it need to warm up? I’m probably stupidly impatient and start out ~90 seconds after starting car and pulling out of garage…


#5

Under those conditions, at what rate is the RPMS cycling? Is it 1000 rpm to 2500 rpm and back down to 1000 rpm within 1-2 secs, or does it start high, then drops to 1000 rpm and stay there? The first is indicative of a vacuum leak and I’d look for vacuum lines that look cracked or degraded. The second is considered normal for a cold engine.


#6

First scenario (most commonly noticed). Pull out from stop sign accelerating enough to travel 1.5 blocks on flat surface to coast 150 ft to a traffic signal. Engine is at appx 2500 when I take it out of gear to coast, between putting the clutch in and coming to a stop, 2-3 cycles where it went from the 2500 listed above, to about 1200, to about 2000, to about <1500, 2000, <1500… maybe 2 seconds to go from 2000, to <1500 and back to 2000. After coming to a stop at traffic signal it’ll settle to maybe 1400 until I pull out.

Second scenario (noticed this eve). I pulled out of a parking lot at the top of a rather long hill, onto a 6-lane divided road with 50Mph limit, heading down hill, once it got up to 50 (not pushing the car hard), I took it out of gear to coast ~.50 mi before heading up the next little hill. It did a similar thing, going from about 3000, down to 1500, up to >2000 (maybe 2200?), down to 1500, up to >2000, down to 1500, cycling 'til I needed to put it back in gear.


#7

[i] How long might it need to warm up? [/i]

A couple of miles. It is best for your car to drive off (avoiding freeway speeds) as soon as you can. Remember that more than the engine needs to warm up. The transmission and suspension also need to warm up, and they will only do it while you drive. Letting your car idle to warm up also waste fuel.

In extreme cold (like -25?F) you may need to idle a minute or two to get the engine to the point it will have enough power to move the car.