'98 Tahoe Thud Noise right after startup! Please help!

Hey Y'all,

I've got a 2WD 2DR '98 Tahoe. This problem seems to be intermittent but right after startup (30 seconds - 1 minute) I hear this loud thud noise. It seems like it is coming from the engine compartment or behind the glove box on the passenger side. The noise only happens 1 time after the car has been started. I've read about about carbon in the pistons and something getting caught in a fan but when the noise occurs it feels like someone pushed the truck from front.

I took it to the dealer a while back to get normal servicing but they couldn't pin point the problem. It's been happening for a long time and my truck has never had any major issues. If anyone has experienced this problem or has any idea what it could be your feedback is greatly appreciated.

Thanks,

atxballer

My gas tank use to make a thud noise kinda like it was popping a dent out or something. Seems that I remember that it did is shortly after start-up as well. Never caused any probs.

NOKUY said:

My gas tank use to make a thud noise kinda like it was popping a dent out or something. Seems that I remember that it did is shortly after start-up as well. Never caused any probs.

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That's exactly the noise it's making. I just replaced the fuel pump, assembly, and harness. So far I haven't been experiencing the noise but only time will tell if it comes back. Nonetheless, thanks for your input.