Malcolmp226

I have a 96 Z24 that has been stored in the winter since it was new. It currently has about 80K miles on it. I drove it to work one day and it ran fine. When I got out of work, the car started skipping as soon as I started it. I had it towed to my mechanic and he checked the codes, nothing. He said the compression and fuel pressure are good. He changed the injectors, coil packs and plugs and it still skips. He pulled some of my gas and let it sit over night to make sure someone didn't put anything in the gas and for water. He can't figure out what is wrong with the car. Anyone had problems like this that can give me some direction? Thank you in advance for any help. I need this thing running so I can get it home for the winter.

Jiyu

If 'your mechanic' changed the coils, injectors and plugs and it still don't run, 'your mechanic' isn't a mechanic, he's merely someone throwing parts (and your money) at the car and hoping he guessed correctly.

'Skipping' doesn't really mean anything to most of us. Does it run? If so, how does it run? Is it misfiring? Does it start easily? Is it a rusty car? Was it raining when it started running poorly? Etc.

Malcolmp226

My car starts and runs but it misfires and has no power. The car is garaged and not driven in the winter so it’s rust free. It was dry when the problems started. I drove to work at night and the problems started when I got out in the morning and drove home. My mechanic has been working on my cars for 20 years and is good about not throwing parts at a car because his customers don’t have a lot of money. My problem has him stumped. That’s why I’m trying here for some ideas.

Jiyu

Much better. Couple possibilities: A car that old that still has the original high-tension wires (from the coils to the spark plugs) may need those replaced, because, like all rubber items, they deteriorate with time.

Also, check for vacuum leaks caused by rotten/cracked or other deterioration in any rubber component leading to the air intake.
It would be very good to see what the spark plugs looked like -they'll tell you what's going on inside the combustion chambers.

On old cars, corrosion can develop between the ground cable between the engine and the car body, and between the battery and the car body, starter, etc. So, an important cost-free first step would be to remove all ground cables, clean the mounting surfaces to bare metal and re-attach. Ditto for the battery cables. Bad grounds can cause all sorts of strange problems. Also, get the battery 'load-checked' Most auto parts stores will do that for free. You can also perform this test yourself if you have a volt meter (they're pretty cheap and an important tool to have). To be clear, "The battery's almost new," or "I just charged it." means nothing. It must be properly tested. Bad batteries can also cause all sorts of crazy probs.
Check the air cleaner, if dirty replace. Clean the Mass Airflow sensor - it's easy, see YT for how to.
Do all the easy, cheap things first.

Buy a repair manual for your car - its filled with all sorts of good info, including tips on troubleshooting. Buy a cheap scan tool or use one of those trick new on-line scan tools.

As far as replacing parts goes, all the parts you mentioned can be tested to determine whether or not they're defective. The repair manual explains how to do that. Any competent 'mechanic' knows how to perform those tests. Injectors are not only very easy to test, they very seldom fail As far as both coils and all three injectors failing, that's impossible.

Here's the most important tip: Generally, the more mysterious the problem, the simpler the fix.

Malcolmp226

I’ll try some of those idea out. Thanks