New issue, well kinda...

[BigMac76]

Ok guys, been dealing with something here last few days that's really driving me crazy. I've got a 99 Z28 m6 and here recently the car has been doing something that's just weird so to say. It will act fine for a bit while driving and then all of a sudden it'll act like it's bogging down. The oil pressure/voltage/fuel gauge, and everything are reading normally and the car will still be acting like it's running but there is no audible sounds from the fuel pump. I can downshift and it'll stay running until I get down to around 1000rpm or less and then she'll die out completely and all the lights on the dash will come on as if you just turned the key on. Now while this is happening, if I press on the throttle, it does nothing at all. Sounds like it's sucking in air, but kind of hard to tell with the exhaust system on the car.
Now if I turn off the ignition key for a little bit, anywhere between 10-30 seconds or more, and turn the ignition key back on, you can hear the fuel pump kick on and it'll start. But sometimes it'll go back and do the whole thing all over again in less than 100 feet after, sometimes 5-10 mins or longer than that. It's not something that you can set your clock to, at times it's pretty random and intermittent.

So here's a few of my ideas as to what could be causing it:

1- Fuel pump: Maybe there is someething going on with it that causes it to shutdown, almost like an overtemp/thermal cutout switch because of it running too hot?

2- Fuel pump relay(s): Maybe one of the fuel pump relays are going and causing it to cutout and act like this? Either one thats under the hood or possibly the one that's in the drivers side kick panel.

This is my first 4th gen so I'm not that experienced with these cars. I am more used to the old iron block 2nd gens than anything. Not sure if anything with the maf if it needs to be cleaned or something with the tps that could possibly be causing this issue?

Has anybody seen this before? Any help would be greatly appreciated because this is driving me crazy and making me want to dump the car and get something else because it's my daily driver.

[My84Z]

I'd say pump but you shouldn't hear the stock pump unless your on top of it they are usually quiet so probably time for a new one either way

[Slowhawk]

All you need is someone like myself to scan the car. Pretty sure I've said this before.

[BigMac76]

Thought that myself too, but wasn't sure if there was a thermal cutout in the pump.

Don, would love to bring the car to you, but unfortunately its my only car right now as my girl needs the other car to get our daughter back and forth from school. Unless you had an opening sometime soon to do it, or I am going to have to start tossing some coin at it piece by piece.

Thinking of going with a racetronix unit, any suggestions? Don't need the top of the line since the vehicle only has light bolt on mods right now. Was also thinking of going with the Hotwire kit as well.

[My84Z]

Just put a fp gauge on it see what it is doing. Probably overworked the pump with the dry kit

[ILuvPizzaTimes10]

ive hardly seen a fuel pump be intermittent. they either work or they don't. so do what john sed FIRST before just throwing parts at it. Then check the wiring to verify you have 12 volts for 2 seconds(fuel pump prime) when you turn the key to ON not start. there is a connector above the rear end in the floor of the car. if you have 4 channel then you should have 2 connectors. the one with the orange connector lock should be the one.

[smokinss]

I agree with Don and pizza on this. Scanning it would be the best thing to do. But like pizza said the pump usually just dies. One of the main reasons I put a fuel pressure gauge in my car with nitrous.

[Slowhawk]

Well, you can keep throwing things at it till you get the right part/fix. Fuel pumps just don't randomly drop pressure under normal driving.


This could easilly be avoided with coming here and having me scan it for 10 minutes and tell you exactly where to look.

[LSX-Nation]

You really should just do that, don't you work in his area anyways or down 495 near 24?

[98 hoe]

At least put a fuel pressure gauge on it and drive it while monitoring the gauge. If it starts acting up look and see what's going on with the gauge. Easy and free.