I know this could be one of a few problems...maybe even as simple as a tune up, but let me run this by you in hope that the specific problem is "common" or has happened to someone before.

First off, the Vette in question is a 1977 L48 4 Speed Manual Transmission. The problems may or may not be related.....

After running for awhile (say 5 miles or so) and with the engine plenty hot, the car seems to miss, or lose power, at low RPM. To be more specific, after coming to a stop at a light, I go to put the car in 1st, hit the gas, and the car wants to stall....and if I catch it right, I can prevent the stall, but the engine power isn't there until she's running high in 1st gear.....the problem does NOT continue through the other gears.

Now, If I don't catch it, and it stalls, its not real easy to start back up....but it does restart. However, the same power problem will be present.

It will go away after it happens and run normally again for another few miles, only to happen again. Its especially noticeable when Im bringing the car into the garage. I have to give an awful lot of gas when backing her up to keep it running.

Now here is the part that may or may not be related....twice when this happened, when I put the car in 1st gear, and let off the clutch, it was as if the car was still in neutral. Nothing happened. I was forced to start in 2nd...but as soon as I do, 1st gear is back. Im thinking this could be a simple adjustment, but transmissions is not my thing, so this I will bring to a shop...but I wonder if anyone else has had similar issues, and were they related??

As far as I know, the car does have only 65K original miles, so it really did not get driven much by the previous owner and I have continued that trend, driving it only once per week for a little bit.

I realize it could be as simple as a tune up, or a vacum leak (but I doubt the vacum leak 'cause I don't hear anything unusual and the problem is intermittent). Keep in mind, the problem only has appeared when the car is hot. It runs perfect until that the first sympton appears each time.

Any idea's????[/align]

 

Once the engine has warmed up, you get expansion of parts. This may or may not contribute to a carb prob. I recommend a tune up and a carb kit.
Your car runs fine in the other gears due to your rpm's are already up. Your tranny will not cause this prob.
This is my best shot. I hope this helps.
(oh ya, change your fuel filter too)

 

Your tranny problem may very well be caused by an out-of-adjustment shifter. There is a procedure where you make alocating gageout of thin flat stock (.644" wide and about .030" thick), disconnect the shifter rods from the levers (tranny in neutral), and insert this tool in a groove/slot in the bottom of the shift levers. Now you adjust the shift rods so they fit the shift levers. This sounds complicated and without the pictures in the service manual, it probably is.

The other thing to check is to ensure that your clutch has the proper amount of pedal free travelwhich is 1.25"-1.5".

 

The poor power/running sounds like the carb's too lean after warm-up, could be the choke also but we need more info on how your able to restart it after it stalls. It seems like a fuel related issue, check the fuel line routing near the engine, filter, charcoal canister and venting. Also since it is on initial warm-up check the coolant temperature switch for the EGR and EFE, these are threaded into the intake manifold or water outlet, check the vacuum hoses for these sensors/switches, if their not routed correctly or in poor shape you can have a vacuum leak at different engine temperatures. Are you getting black smoke on re-start or do you have to pump the throttle alot to get it going?

 

The restart is fairly simple...just like any other hot engine start. I don't have to pump the gas, or do anything out of the ordinary. It starts pretty easy, but doesn't run great at first. Very rough. That will go away once I get moving and into say 2nd gear, and whats strange is the rough running/idle won't start until I try to move from a stop. In other words, Ill come to a stop, and everything is normal....normal idle, etc., but when I put it in gear, and step on the gas, there is a bad hesitation, which will turn to a rough idle, and stall.

On restart, I did not notice black smoke, but I wasn't looking either. It did happen in the garage once, and upon restart, I did not see any smoke, or smell anything out of the ordinary and I would think it would get trapped in the garage if there were smoke.

 

I had the same problem and I done a complete tune-up, but to my suprise the problem was still there. The only thing I didn't change was the plug/coil wires. My problem was fixed with a $4 coil wire. I guess at idle when the lope of the engine making the car vibrate was causing enough movement to make the broken wire loose connectivity and then causing the carb to load up. If you haven't already changed the wiring. I would suggest trying a $4 coil wire.
When my vette was acting up.... I would have bet money that it wasa fuel issue... I'm sure glad I didn't make any wagers. Hope this helps!

 

Hi 74vette, thanks for the input about your similar problem, but one small item changed between '74 and '77, Rick's Vette has HEI with no seperate coil wire, but we can't rule out an ignition problem yet, stay tuned.

 

I had hope for a second.....but then I realized the same thing...no coil wire.
Oh well. I didnt get a chance to play with it today, but I surely will during the week and I will keep you up to date. I hope the updates will help someone else as well.

 

Hi RickStehr and welcome to the forum. I like to take "Baby Steps" when I'm trying to find a problem, have you looked at the accelerator pump in the carb? You should get two streams of fuel into the carb when you press on the gas. Did you check that the linkage is connected and properly adjusted? Did you change the in carb filter or remove it for a test? Look at that and let us no the results and we'll go from there. PG

 

Ahem.

Mr. Stehr, you got duplicate posts here

https://www.corvetteforums.com/m_374..._/tm.htm#37485

and there no reason for a re-plyerto ask questions that someone else has already asked.

If we could close one of 'em there, mods...