Mechanic help needed asap..please.
 

Over the past couple of weeks my truck has started to backfire. I have a 98 2 door tahoe with a 5.7 liter vortec. Well Today, along with the master cylinder I went ahead and replaced the spark plugs and wires, and fuel regulator...but it still keeps back firing. It happens mostly when I take my foot of the gas, it starts to do it very rapidly, and its Idling ruff.. when I have my foot on the gas, it doesn't do it that much..it also acts like it wants to die on me every so often..I`m dropping it off at the shop tomorrow, not sure whats up with it..I `m thinking the compression is off, or the fuel pump..I also noticed that I had a hole in my muffler, while I was bleeding the breaks maybe thats the reason? I dont know...and Ideas ?

Probably not fuel pump. Sounds more like timing.

Do you mean the timing belt? or is this something else ? and do you know how expensive this might be?

the hole in the muffler is probably just popping when you let off the gas and the unburned fuel gets there and ignites with the oxygen from the hole
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Fuel pump, vacuum line, coil, water in the gas, etc. Start with the cheap stuff and throw in a bottle of "Yellow heat" and check under the distributer cap for any condinsation. You didn't get the engine wet at any point in the last week or so, did you?

I wondered why everybody was jumping under their tables in the Dotte. The ol' Tahoe backfire.

Possibly spider injector.

Would that cause it to Idle ruff also, and act like it is dying?

No water in the engine lol. I replaced the distributor cap today when I did the tune up and didn't see any water. It has new heads on it and a new intake manifold..but I did notice when I took the top of the fuel injector off that it was pretty dirty, didn't know if that was from the fuel modulator that I replaced being bad or not.

That would be funny if ...........If I didnt live in Johnson County. ;)

I would still go over to the store and invest in a $1.00 bottle of Heat. Get the Heat in the yellow bottle. One of my rigs was doing about the same thing last week and that cleared it right up. A little water in the gas will raise hell with the way it runs. It will only cost you $1.00 to find out.

Thanks..On my way right now.

Those engines, (while great) are notorious for having the valve guide seals leak and go tits up. It doesn't sound like this is the case here but some of the symptoms are consistent. When you start it up, does blue smoke come out of the exhaust?
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