1999 sub just quit going down freeway.

[010175]

I have a 1999 GMC with 280,000 miles. No engine light on. I was going down the freeway and the engine light flashed 5 times and the engine quit. Left 4 ways on and the battery went dead. Towed home. Checked code and it was p0304. Because the battery was dead for a few days I don't know if it's from back then or just now with me trying to start it. The fuel presser is good and it holds presser. The engine try's to start I think. It stumbles and simi locks like it's trying to fire but not enought to keep it turning. fuse's look good, the ones I know of. Any ideas? I am a shade tree guy and don't mind throwing a few parts in it on the guest. Thanks Dave

[777stickman]

Need to know what motor. What some folks consider good fuel pressure most of the time isn't, so need to know that also.

[j cAT]

Originally Posted by 010175

I have a 1999 GMC with 280,000 miles. No engine light on. I was going down the freeway and the engine light flashed 5 times and the engine quit. Left 4 ways on and the battery went dead. Towed home. Checked code and it was p0304. Because the battery was dead for a few days I don't know if it's from back then or just now with me trying to start it. The fuel presser is good and it holds presser. The engine try's to start I think. It stumbles and simi locks like it's trying to fire but not enought to keep it turning. fuse's look good, the ones I know of. Any ideas? I am a shade tree guy and don't mind throwing a few parts in it on the guest. Thanks Dave

with a 1999 gmc suburban the fuel pressure need be key on eng off 62-65psi. it may start at a slightly lower pressure like 55psi maybe. p0304 is cyl4 miss fire. low fuel pressure can do that. if this is the only code and you have the pressure tested with a pressure gauge then this maybe a distributor problem/ICM etc.......... on these vehicles the distributors do fail @ 175K miles and higher. check for wobble of the rotor . my guess its the 350CU OBS...

[010175]

Triple 7 and j cat thanks. I replaced the distributor cap as it had a hole cut thru it via spark. The car started up. I am now replacing the spark plugs. With 280,000 on the 5.7 and I have never changed the plugs, wire, cap or injectors. It's time! Will report back when done. Thanks Guys

[j cAT]

Originally Posted by 010175

Triple 7 and j cat thanks. I replaced the distributor cap as it had a hole cut thru it via spark. The car started up. I am now replacing the spark plugs. With 280,000 on the 5.7 and I have never changed the plugs, wire, cap or injectors. It's time! Will report back when done. Thanks Guys

when you get a new GM truck it won't run this long that good ! maybe 100K if your lucky...

[010175]

All work done! Plugs came out with cold engine after 280,000 (purchased new) with no problems. Thanks again

[j cAT]

Originally Posted by 010175

All work done! Plugs came out with cold engine after 280,000 (purchased new) with no problems. Thanks again

post a picture of one of the plugs.. what was the plug # ?

[ASJT3]

Originally Posted by j cAT

post a picture of one of the plugs.. what was the plug # ?

Agreed, would be interesting to see those plugs.

Not to hijack this thread but of the '96-99 Suburbans, is there a preferred year? My 99 was great but had so many electrical gremlins and I heard this may be a common problem with the 99s.

[010175]

Photos

[010175]

One at a time I guess.

[010175]

280,000 mile cap with hole arced into it.

[010175]

280,000 mile plug.

[j cAT]

Originally Posted by 010175

Photos

the gap looks huge but the burn still looks good.

the engine must run better now with more power ..

usually old plugs/plug wires and cap rotor cause slow cold starts.

[010175]

It does start faster. This is my back up car so I can get to work! 89,000 miles.

[j cAT]

Originally Posted by 010175

It does start faster. This is my back up car so I can get to work! 89,000 miles.

NICE CADDY.. MPG 7 on that one. good thing gas prices are down to below $2 / gallon... last I checked here its down to $1.80.