Rough engine + some stuff

Asked by Jul 01, 2016 at 07:18 PM about the 1999 GMC Suburban K1500 4WD

Question type: Maintenance & Repair

So, I have a 1999 GMC Suburban, right now the engine is running really
rough. SO I replaced the spark plugs, the spark plug wires, the rotor, and
distribute cap. That only alleviated the problem partly, but now the exhaust
smelled of gas.. So next I replaced the fuel pump relay, fixed two leaking
vacuum tubes, and replaced  the idle air control valve. Same effect, runs
better but still rough, got rid of the gas smell. The check engine light came
back on and the dia computer said the 7th spark plug was misfiring, so I
pulled it back out and it was  pretty dirty already. SO I cleaned it and
reinstalled it, gas smell came back. I know one of the heads is leaking oil
on the left side of the engine, could that be getting in the spark plug
chamber and cause the issue?

8 Answers

40

I had a 1997 Tahoe with the same problem a few years ago, and it didn't stop came to find out i took to a shade tree mechanic, he took out the spider injectors cleaned them and put them back in and the little smoking stop, but he told me i needed new ones, I mean it drove like a new truck, but I bought the new one,cost like $265 on ebay, but it fix my problem, I drove for like 4 months before I put the new one in, hope this helps you.

30,805

does it do the same thing all the time?? idle-load ???? k

It does it while driving too, so I don't know, and I'll check out the injectors

30,805

im sure the fuel pressure was checked and the fuel filter replaced???

Fuel pressure was fine, but I haven't replaced the fuel filter..... I'll try that

30,805

let us know...need to find out if it has a weak/dead cylinder...

nope, not that

I'm thinking I may have a weak 7th cylinder, but I don't really know how to figure out if it is or not.

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