I just purchased my 1st Corvette, it has been sitting for a little over a year. The owner of service center where I found the car stated he tuned it prior to it sitting, plugs,wires, dis. cap...., However, he also said it would "cut out" upon heating up, sure enough it did. Thinking it may be a plugged cat, I removed it for a test, no luck. I do not have any diagnostic equipment. Any suggestions for a shade tree mechanic?

 

The cats won;t cause an engine to "cut-out" ....a plugged cat will cause it to be very slow to rev and lack any sort of power. Not misfire.
Misfiring is always fuel or poor spark. Spark is the same hot or cold unless the plugs are trashed, so that leaves fuel...(I's easier than that...the injectors are famous)

What i can tell you without any more info is that you probably should talk to Jon.

That motor has some junk injectors that are plugged and tired. For $250 I can almost assure you of improvement. All L98 engines need this upgrade...ALL. Between ethanol and time, the inj used on C4s are now trash. And they do what you are seeing when they fail....
Ohms test these to see what I mean..cold and hot.

Use good parts, NOT gimmick plugs & wires. Delco parts in the dist and brand sensors. Wheel bearings too...the cheaper you go the more often you get to do it again.... Parts can be costly so shop around. Corvette aftermarket is full of vendors...always search FleaBay for parts that you cannot find at the usual stores...Vette salvage is huge business.
Join your local Corvette club to learn what shops are good and what works and what does not.

There are a few things that you MUST have if you are going to own a C4...unless you are very wealthy and can afford to throw parts.....

#1 and the very first thing you need to do..before anything else....

Get a FSM. Not a haynes or childrens manual, a real GM FSM. The 2 books that will save you thousands of $$ over the course of a couple yrs...
Call Jon next.

then....the tools

fuel pressure test gauge
Noid lite
spark tester
DVM or ohm meter
test lite
code reader or a box of paper clips
Torx bit set, allen set, long bits.
Thin 10mm open end wrench, 3 -10mm sockets in 3/8 and a couple of 1/4 drive.

Thats it !

Get your FSM and use that to diagnose.

In the near future you will be doing wheel bearings/hubs, U-joints, possibly weather strip (if needed) and you'll need a sucker for the rear end. (it has no drain)

Once you get the book it will tell you how easy the inj will be. I can tell you how much of a difference that will make! Search YouTube for video on the work being done. Great info there on 'how to' all kinds of vette repairs. Search YouTube for FIC.

Its an everyday thing around here...someone cures their problems with new Bosch-III injectors.

The problem you have is not a big deal..just a saturday afternoon in the garage. THEN it'll run right hot or cold.

Good luck and have fun !
welcome to Corvettes!

 

I agree with leesvet, I have a 91 and it was sluggish when I romped on it. Checked the resistance and found a couple of injectors bad. Called Jon at FIC and he sold me a set of Bosch 111 injectors and my car runs great. Procedure looks daunting at first but with a FSM it's really not that hard. Trouble is when you get it apart you will want to dress up the runners , valve covers,plenum etc. but thats the fun of it.
Good luck

 

if you don't have fsm or another manual, you can check the ohms on each injector. push in the wire clip on each harness plug connector, lift plug off, check terminals on eack inj. don't worry about getting the connectors mixed up. if cold, the readings should be above 10. if they are original, they are due for replacement. but, the list of things that cause "cuts out" is long.

joe

 

Thanks guys, look forward to working and learning!

I did ohm the injectors, this what I found,

5 of them ohmed at 16

1 at 10

1 at 7

1 at 4

Guess this will be my next step right after I get a FSM. Anyone have a procedure instructions or link to do this injector replacement? Thanks again!

 

You might want to go to the above Sticky and click on Tech Tips and then click on the third one down. There are some good video's.

Mac

 

Been into replacing injectors as time allows for about a week now. Have FSM in hand and FIC injectors should be here tomorrow! Been doing alot of cleaning, TB, plenum, runners, etc. For my peace of mind I have replaced valve cover gaskets, pcv, thermostat. Question at hand now do go ahead and replace EGR valve while right there?

 

I bought the EGR from Advance Auto Parts using one of their coupons (check fatwallet.com for the coupon codes) and join fatwallet.com if you want to earn another 5 percent of the purchase price. My mechanic pulled the EGR and sprayed a ton of carb cleaner into the orifice. He then took a bent wire coat hanger to the passages. He does this everytime he replaces an EGR. The carb cleaner goes everywhere, so have a few rags handy.