Random multiple culinder misfire

multiple cylinder misfire. I am not sure but when starting I think I smell gas.

and wires are about three years old. Truck has been running fine until on my way home last night. So it seemed kind of sudden.

fluctuate as they should.

yes, check it in with someone that knows what they're doing and PAY THEM. you don't, you won't, and you keep cutting corners. you'll never fix it by randomly replacing stuff, and /certainly/ not by asking the same questions over and over and ignoring what people tell you.

multiple cylinder misfire. I am not sure but when starting I think I smell gas.

and wires are about three years old. Truck has been running fine until on my way home last night. So it seemed kind of sudden.

fluctuate as they should.

Look if you dont want to respond dont. This is a separate problem from what I had exeperienced several months ago. That problem was solved by replacing the distributor cap.

When did you last add gas? Check the cap for moisture. Did it rain or get damp before it started running rough?

No, the weather has been nice. No rain. I got gas 200 miles ago. (Last week some time).

This all happened late last night so I have not done much diagnoses other than hooking up the scanner. I also looked under the hood in the dark and felt around on the wires. I saw no sparks or anything.

OK then check the cap / rotor to make sure it's OK I've seen rotors and caps fail even when new. Especially the current parts...

ignition module, wiring, coil failing.

ago and the module also about three years ago. I know that does not necessarily mean they are good.

Do you have a full function scan tool, or basic one? After seeing a P0300 Random Multiple misfire, you need to next look at the misfire counters for every cylinder. If they are ALL really high I'd check fuel pressure next because you said "spider injectors" and that makes me think Vortec, which need a good 65 psi all the time. If that's fine, I'd swap in my spare ignition module and coil, because that's fast and it's really hard to test drive a car while using an ignition scope unless you have a dyno or a stuntman-assistant.

GW

Don't even know what engine he has, but what I've found for the GM 3.1 multiple cyl misfire is caused by failed coil pack/ignition module, as you say. Three different cars. The cat really heats up too, and you can see/smell that. I replace all packs and the spark module at once, because the one time I just did coils, the spark module failed shortly afterwards Could have been coincidence, but I figure it's age and cycling killing them, so i just do them all.

multiple cylinder misfire. I am not sure but when starting I think I smell gas.

and wires are about three years old. Truck has been running fine until on my way home last night. So it seemed kind of sudden.

fluctuate as they should.

It is indeed a 5.7 vortec. The spider injectors were replaced by me in December. I used the AC delcos I believe from NAPA.

I am definitely smelling a little gas when first taking off.

multiple cylinder misfire. I am not sure but when starting I think I smell gas.

and wires are about three years old. Truck has been running fine until on my way home last night. So it seemed kind of sudden.

fluctuate as they should.

Oh, and I just have a basic scan tool. I have no misfire counters.

multiple cylinder misfire. I am not sure but when starting I think I smell gas.

and wires are about three years old. Truck has been running fine until on my way home last night. So it seemed kind of sudden.

fluctuate as they should.

so pay someone that has the proper tool!!!

and so it goes - you want advice, but you don't want it because you think you've already done it...

night and it looked ok.Just some white residue on the terminals which I thought was normal. Not sure where to go from here.

ChevyForums.com ? FullSizeChevy.com ? ChevroletForums.com ?

Did you try spraying water from a pump bottle onto the ignition wires? I h ad a random stumble with wires that looked perfect, but at one spot one of those wires would always arc when wet or if it got too close to metal. Th e insulation looked perfect even when I made several thin slices through it . The smell of gas could indicate something with the vapor recovery system, a nything from a broken or loose hose, clogged charcoal canister, solenoid va lve, or check valve. I was getting a raw gas smell and pinging until I too k my car for its emissions inspection, and I think it was their pressure te st for the fuel tank that unstuck something.

How are the electrical connections to the fuel pump?