Hello,
I am new to this forum. I have an 84 vette with only 34K miles on it. As you obviously can tell the car is not driven that much since we are trying to keep the miles low. Anyways when I do drive it which has been daily the last week it idles great and runs great at highway speed. However when I begin to accelerate it runs very crappy. I recently put a bottle of injector cleaner in it and I am wondering if that is the problem. If it is not what could it be? When I mean rough, during acceleration it will almost stall it sputters so bad. Please let me know what to check. I am changing the plugs and wires tonight so that may help.

Solomon

 

When was the last time you filled up? Could be as simple as bad gas.

I'm assuming the car sits most of the time, did it start this immediataely after you brought it out of storage or did it drive alright for a while and then start this?

 

It started immediately. I was not running this rough until I put the injector cleaner in it. I also changed to a K&N filter. Could that be it? I did not reprogram anything for the filter. Is that even neccessary?

 

It's not necessary to reprogram anything for an air filter.

If it wasn't running as rough before the injector cleaner then it is possible that is your problem.

Disclaimer: THIS IS ONLY A THEORY AND MIGHT BE FLAWED BADLY

The injector cleaner might have broken loose some larger particles of buildup somewhere upstream of your injectors. Perhaps it can't really disolve these particles effectively and they have moved downstream and clogged the injectors.

Just a thought, might also want to check on the fuel filter. You could have broken some crud loose and gunked it up. Then at idle and cruise you can get enough fuel but at WOT you're running short.

 

:yesnod: I agree with the injector cleaner theory. My mechanic told me to never use the stuff. I remember once about 14 years ago my 84 ran like that for a day or 2 and it seemed to work itself out. Could be bad gas too.

 

Thanks for all the information on this topic.

 

I just sent you info on changing wires and plugs, then saw this post as well. My car has twice the miles as yours, but sat for 3 years. Change the fuel filter (bottom right hand side of the car, just behind the front wheel well). Mine ran ok when it was cold, but got worse when it got hot. I thought the catalytic converter was clogging up, so I drilled two small holes in the pipes in front of that, but that wasn't the problem. HOwever, if it had been, the car would have run properly, then you can decide to leave the holes, or replace the cat. (I know have to weld the two holes shut, as the sound is bad). Next, if things stay the same, start the car and look at the injectors. The fuel coming out should look like a fine mist in the shape of an umbrella (no drops of fuel, just a very fine, even mist) . If it's not, it's probably the throttle bodies need rebuilding (easy and cheap if you do it yourself). If you do that, I'd replace the fuel pump as well (most online info says the pumps greatly influence the operation of the car - my pressure test said fuel pressure was ok, but car ran better after I replaced the pump). Pump replacement is also cheap (under $100) and easy if you do it yourself.

 

You may want to upgrade to a 85' fuel pump if you do decide to replace the pump.

 

clogged cat? :confused:

 

Replace the coolant temperature sensor that is located at the front of the intake manifold. They have a tendency to go bad and the new one is an improved design over the original. You will have to cut and splice in new wires. Also do all the normal tune up items. Good Luck I love my 84 too.

 

Quote:clogged cat?

I don't know about a clogged cat but, the media in my 86's cat was so broken up, do to age, I literally took the cat off, and dumped the media into a garbage can. No hollowing it out or nothing. I had an 86 Rustang that had the same problem. That stuff brakes down over time.

 

Surfidillo has got it. Fuel filter.

 

Guys, sometimes I have the same problem as 84cherry, usually when I don't drive it for a couple of days, or I get some regular gas. My vette has also been an apparent daily driver for everyone who has had the car before me, because it has close to 200k miles on it. Anyway, I have replaced the fuel filter, cts, tps, switched to K&N air filter, raised the timing slightly, changed all the plugs and plug wires, always run premium gas, basically nearly every minor thing possible, and my car persists to miss at idle. I don't know what is wrong with it, because it runs like a dream save for that. Any help would be appreciated, thanks.

 

What is an good idle speed for an 84. I recently changed the plugs and wires and it is now at a higher idle. (about 11)??? What do you guys think?

Thanks,
Solomon

 

Idle=750 RPM

If you messed with the TPS then it has to be reset at 54 milivolts. If it is set too high, that will make the car idle high. Also a bad EGR valve, switch, or silinoid will also make the car idle high.

 

What is a TPS? And if I do need to reset it how do I do that? All that I did was change the filter to k&n and the plugs, wires, distrubutor cap, and rotor. Would that change the TPS?

Solomon

 

No, the TPS is mounted on the side of the throtle body. If you didn't touch it then it is probably ok. Incase it does go bad you can set it with a volt meter. I would just look around the engine and check all the silinoid plugs to make sure they didn't get disconnected. If they become disconnected then that also could make the idle go up. Especially the EGR silinoid. That has happend to me before. Also check vacumm line to see if they are connected as well. If you changed the rotor you could have knocked one of them off. So in short, check all silinoid connections and vacumm lines.

 

Thanks for everyone's help. The car is running better than it ever has. Thanks for all the tips.

Solomon

 

Here's an idea....get a March Pulley system the "amp' setup with 3 pulleys...looks ggod and gives you a little more umph....
Just my thoughts.....
From my '84
tony
:flag :flag

 

Mine idles at 800-900rpm when started and 600-700 when warm.
I got an question for you guys. My 84 jumps when I have my foot on the brake and put it into (D). Is this normal? The tranny is an '89 700R4 with a shift kit and a 3000 stall converter. Thanks.