smittygj

Wondering if anyone has any idea what my problem may be.

I have a 1999 K1500 Suburban with a 350 in it.
Bought it used two years ago. Currently has
about 164,000 miles on it.

Have had to replace fuel pump twice (last time
about 2 months ago). Other than that, has been
pretty reliable.

Just in the past couple weeks, it has started bogging
down on acceleration. If I ease into the pedal, it's
ok, and usually gets up to speed, but if I step on it,
it boggs down and even starts to make a popping noise
from under the hood.

Replaced fuel filter, no change, it still does it.

One thing I have found is that if it starts to bogg down,
if I put it in neutral, turn the key off, and then start
it back up, problem will go away for a few minutes,
and it will accelerate normally.

I've also tested it sitting still. I can start it, and
rev it up to 3000 rpm or so, lets say 5 times. Out
of those 5 times, it may rev up fine 3 times, and
bogg down the other 2.

Any thoughts as to what it may be?

Thanks in advance!

Smittygj

old dog

might be the converter ,but i would have it put on scanner asap !

smittygj

Took it to Autozone to have the codes read.
Service Engine light has not been on, but I think
it did come on briefly when the problem started.

Looks like you may be right.
It returned two codes.

P0420 Catalyst efficiency low - bank 1
P0430 Catalyst efficiency low - bank 2

This thing has two catalytic converters.
Is it possible they both are bad and both
at one time?

smittygj

Replaced the converters (both as it is all in one direct bolt on replacement).
Problem still exist.
Check fuel pressure at test point and it's reading 60 (which is
what it should be).

What do I check now?

dwcchevy99

My suburban is doing the same thing, did you ever find out what the cause is?

Thanks

David

barnyardmech

I don't know if this will help. On 06/02/08 I replaced the fuel pump because the truck would not start. It worked great!~ Then in August the truck started bogging. The harder I accerlarated the more the truck gagged, until I let off the accerlarator. The problems only worsened to where once I was able to pull over and turn the truck off and it ran good for another 10 miles, to bogging after 3-5 miles. so, I changed plugs, wires, cap, rotor, both converters, bank 1 sensor 1 and bank 2 sensor 1, and fuel filter. After spending all this money the truck still ran pittiful until I bought a fuel pressure gauge and found that the two month old fuel pump was only pushing 50 psi. I have heard the horror stories about how Chevy only "likes" AC Delco parts. Well, when it comes down to the big parts, I'm a firm believer. This to say, if your fuel pump isn't AC Delco it probably is the problem. Don't go to the shop ~ go and buy a fuel pressure guage (tester) for $40 and check your fuel pressure yourself. The shop will charge you the same price but you won't own it for the future. Screw the end to the fuel rail under the hood and turn the key to the ON position to activate the fuel pump. The gauge should read over 50 psi. If it is 50 or lower then it is probably the PUMP.

QBert

there have been plenty of stories of non-ac/delco fuel pumps failing after only a few months. airtex and the other brand (forget the name now) usually will develop problems.