94corvetteC4

My 1994 corvette is a P.I.T.A. and its in such good shape to be having all these issues. The car only has 105K on it and the problems just keep coming.

Purchased in September 2015 and drove it for almost a year with no issues except that the AC which was fine when I bought it no longer worked the next spring. I had it fixed and it worked all last summer. Then in October the Opti took a dump so I fixed it. Get the car running with the opti swap and I have a high idle, 850rpm, that I cant seem to resolve. Then in November the power antenna ribbon broke. Then I had it painted this month and got it back with a blown headlight so I replace both headlights. Last week it got a little warm here in Ga so I turned on the AC and its not working again.

Now for the newest issue. This week it started skipping. I start it up in the morning and take off for work and it skips bad. I get about 3 miles down the road and it clears up and runs fine. I leave work after the car has been parked all day and it skips. Again I get about 3 miles down the road and it clears up. I notice it seems to clear up around 130 degrees so today before I leave work I let the car warm up to 135 degrees and I take off and no skipping.

So it appears the car has a misfire until it reaches 130+ degrees then it fires just fine.

Has anyone had this issue? It just blows my mind that a car will skip when its cold and not when its warm. I have always know a misfire to be permanent as in it will misfire all the time till you find the cause and repair it.

The problems are starting to pile up on me, they are popping up faster than I can repair them.

1. high idle
2. no AC
3. broken power antenna ribbon
4. misfiring engine

I need to fix these and dump this POS and I just had it painted and put all new weather stripping on it, what a waist.

BrandensBeast

We all know how it feels, hell my 2006 GMC canyon with 67k miles has had more things break then either my geo metro my 84 or 89 (all of which have had more mileage, and are older) which is hard to say as the 84 was in such poor shape. We know how it is, don't give up on it, when things break, make them better

jay23ls

Sounds like you passed the point of wanting to keep investing time and money into it. Older cars will always come at a cost. When the costs are too high its time to get... A civic or corolla or sentra..

BLUDICE

My '94 has 96k on it - got it last Aug. It's a 23 year old computer on wheels - so there's going to be issues and more issues will occur as it gets older - learn to live with it or get rid of it. The "miss" issue may be the temp sensor on the water pump - mine acts up sometimes - just unplug it and replug it in to see if it improves the problem. As far as the other problems - if you can't resolve them from help on this site - which it very good - then seek out a corvette "mechanic" - they are out there - maybe a Chevy dealer - I have one locally. BTW these cars can give you some real pleasure - if you are a true corvette lover - but your car may not be the one that's going to give you that pleasure. If that's the case find another one - good luck.

94corvetteC4

Its not really the cost. It's the car having things break faster than I can fix them. If it was a few things here and there I can deal with it but this car is having a new issue every couple weeks. It was a great car for the first year I owned it but not so much now. And the issue with the high idle that so far I have checked everything that will cause it and found nothing wrong and the new issue of the misfire that I'm sure is going to be a P.I.T.A. to resolve since its comes and goes and isn't throwing a code either. It goes away at 130 degrees which meens I have about 4 - 5 minutes to find the problem before it goes away and I'll have to wait several hours for the car to cool back down before I get my next 4 - 5 minute window.

ToniJ1960

maybe a vacuum leak? warm engine needs less gas. Do you have a scanner?

hcbph

Does yours have and IAC? I've had intermittent issues with the IAC, when it's buggered up, it runs like crap. Turn it off and let it warm up a little and it ran just fine. Took a plastic faced hammer and gave it a couple of raps and it's not acted up in a while. It's on my list to replace at some point in time.

billschroeder5842

Sounds like an Opti again?

The other stuff is the cost of a near 25 year old car. I bought my 91 ZR1 in October and have put nearly 5k in it (radiator, four amps, ECM, oil cooler hoses, rear brake calipers and more nickle and dimes) Sorry, it happens to us all.

FOURSPEEDVETTE

By your own comments as in Ex: "BS" "POS" "P.I.T.A" "DUMP" and "WHAT A WASTE", you need to sell it and be done with it. Doesn't sound like you are a real car enthusiast who would certainly expect things to be breaking on a 23 year old car, and then dealing with them accordingly. If it's become a problem for you, as it seems to be, sell it now to someone who will tollerate its age and problems better. Buy something newer. Lots of things can and will go wrong with a 23 year old machine. It's the nature of antique car ownership. If you decide to stick it out and keep this car, it won't be long before you'll be proud of it once again. It's still a Corvette!

1993C4LT1

​​​​​​​yup, sooner or later, it will. Just remember this, you still aren't into it for 50k like you would a new one. And yes OP, the problem you are having sounds similar to an IAC problem I had.

gdl2165

My first thought with the high idle was a vacuum leak as well. Just curious, do you have the high idle just when cold or does it continue to idle high once it's warmed over 130 degrees? Wondering if these two issues may be related.

On the AC, did they replace any parts last time or just recharge it? My 96 AC was working fine last fall but when I went to use it last week there was nothing. I looked around the lines for signs of a leak and saw the high pressure line was oily on either side of the service port. Research told me this is a common issue. The port just screws out of the line, you can get it from various places. You obviously have a leak somewhere and no guarantee this is it but it's something to look at at least.

FAUEE

I've had my fair share of things that need replaced on my car as well. It's the nature of the best with a 25 year old car, there's a reason they're 20 times cheaper than a newer one.

The fixes is sort of part of the fun. It's a project somewhat, and you just sort of learn to love it, or you get rid of it and pay lots more money for something newer.

Sounds like a series of easy fixes to me.

Patsgarage

I think most of us have been where you are with a car at some point. If the car is your DD and you need it to get you to work everyday little things can add up, but if it is a weekend car or just a toy, try parking it and not looking at it for a few weeks. The newest C4 is over 20 years old, things are going to break either one at a time or in bunches. Your car is just hitting a rough patch right now. Go back to it in a few weeks and fix everything one at a time then enjoy the summer.

v8vette84

I'm a little distressed that you are calling the car a POS for some fairly minor issues besides the Opti. (which BTW if you know the car has it then research it and find out how to avoid opti failures.) Also 850rpms is barely a high idle... Did a shop install a parts store opti from advance or autozone? That said I have seen many shops (Even GM dealers) screw up opti installs. Or did you do the install yourself? I personally seal my optis with sensor-safe silicone as the parts don't always fit together as well as I would like but regardless of that I have NEVER had an opti fail on me. Hell on my L99 Caprice I'm using an old Mitsubishi sensor I had sitting in my toolbox's "Opti Parts" drawer and it's working great. (I only changed to that sensor as I was doing the waterpump and wanted to do a cap/rotor and the sensor on the car was a no name.)

Leaking A/C systems is so common on older cars it's not even funny. Hardly a reason to call your Corvette a POS. Most shops don't do the required work of replacing all the seals to fix an A/C problem. Most DIY'ers don't either. The car is 23 years old, the seals are dry and shrunk. Get new seals in the ENTIRE system.

Power antenna ribbon? The Ground strap or the part that makes it go up or down? Either way just replace it or the motor assembly. Again the car is 23 years old, most cars with power antennas don't make it past 10 with a working unit... Neither of my 96' Caprices made it very long with a working power antenna, unfortunately.

Maybe you should just sell the car, if you can't handle these common issues then you probably shouldn't own the car. You will have a heart attack any day otherwise.

Not trying to make you feel dumb but these really are not major issues. I will give you credit for the misfire though and that is one thing that pisses me off when it keeps reappearing. I chased a misfire on my other L99 Caprice and changed the opti and plugs, coil, ICM, grounds and I found out it was the wires arcing. Changed the wires and the misfire returned, turns out the new wire was rubbing on a metal bracket just enough to wear through the sheath and let the spark jump to ground. I had to rev the car in complete darkness to see the spark. Good luck!

ghoastrider1

I get tired of fixing things too.. and then I drive it and all is right in the world.

scrappy76

Sounds to me you saw the corvette thought it was awesome. figured it was soo nice that there is no way you would ever have issues. As far as I am concerned if you went a year of driving a 23 year old car on a daily basis without a single issue, you did awesome. Now comes the time the car is asking you to return the favor and replace its worn out parts and you start stopping your feet and whining.
Is this your first old car ? Sell it and let someone enjoy it.

And my idea of a piece of crap is a brand new car you just paid $ 45,000 for and its at the dealership for recalls.

haxxx

Your misfire is could be a vacuum leak with the intake gasket. This would also explain your high idle. It stops misfiring when hot because it expands a bit and seals itself up. You can try tightening the intake bolts. They become very loose over time and should be in the 30ft/lb range. Make sure to look up the exact spec and tightening sequence. You may need to replace the gasket. Tightening the bolts may get you by for a while.

You can also test this leak by spraying water along the intake near each of the runners for the cylinder and see if the engine sucks the water in and bogs down.

94corvetteC4

Thanks for the responses.

First I would like to say that a few are butt hurt that I called this car a P.O.S. but I call it the way I see it. I will be 50 years old in a few months and I built my first car, 1970 Camara RS in 1982 at 15 years old. I have built cars ever since. Buick grand national, big block 1987 Monte Carlo SS, Dodge Charger, fox body mustang, 2007 Mustang GT/CS, 1979 malibu, Chevy Nova and I might be forgetting a few. All of them were ok/nice cars when I got them and perfect when I finished. I mostly buy new cars off the lot these days. My wife's car turned 350k last week and the only replacement parts over the 16 years and 350K is an altinator, vacuum canister, 1 catalytic converter and an air/fuel ratio sensor. The rest of the car with the exception of regular maintenance items is factory original and it runs like a new car. None of these cars have the issues this corvette has which is why I call it a P.O.S. this is the worst car I have ever owned. It has problems popping up all the time. This is not normal for a car of any make or model to have these issues plus others I have repaired with only 105k on the car.

Now onto the issue at hand. This morning on the way to work the car was misfiring all the way to work, even at 185 degree engine temp. I thought about it being the option because this is similar to a symptom I had with the old opti. The only difference is that the old opti before it died would cause a misfire under load only and it was just one or two skips and done. What I mean by load is adding more throttle to go up a hill without down shifting. I would get a skip or two, sometimes no skip at all. The skip I have now is all the time, load or no load and the best way I can describe it is rappid fire one after the other.

The high idle showed up when I installed the new opti. Before the new opti the idle was normal, around 650rpm. On a cold start the car would jump up to about 1200 - 1500 rmp then settle down to 650 rpm pretty quick. After the new opti install the cold start hits 2000 - 2200 rpm then settles down to 850 rpm. This is the vented Petri opti. I'm starting to think the vacuum leak I haven't been able to find is in the opti and with all the rain we have had lately has gotten moisture into the opti. Sounds plausible.

I was told their is two temp sensors on my car and that one, if bad, will cause the car to run rich which could be the cause of the misfire. I'm going to look into this today.

If it's is the opti that's about to take a dump I will find out when it leaves me stranded. This is the third opti on this car, the next one will be #4.

1993C4LT1

Is 850 rpm with the car in gear? FSM states my 93 auto should be 550 rpm in drive, warm engine. That is with the AC off.

94corvetteC4

Forgot to add that the car is a 6 speed.

Someone mention leaky intake. I did notice a wet oily film on the passenger side of the intake and head near the fuel injectors. I'll check the bolts to make sure they are tight.