99 SS Power loss hesitation at partial throttle.

Hello all, I spent the better part of the morning searching the forum and I haven't really come up with anything conclusive so I figured I'd ask some questions.

I have a 99 SS convertible, about 92k miles, has the SLP whisper lid + K&N, and MAF screen removed, other then that it is stock.

I have only owned this car since the 70k mark, but as far as I recall I have always had some varying degree of this problem, which is:

While accelerating, there seems to be a throttle range where the car sort of "falls on it's face", loses power, or has a hesitation, depending on how you want to classify it.

After reading other posts on the forum, I guess it could be an RPM range, where it will accelerate hard, then hesitate, then take back off again at a higher RPM, I am going to do some more testing tonight, but usually to compensate for the hesitation I will put more foot into it.

Basically to me it seems like at 0-30% throttle it accelerates fairly well, at 30%-60% it actually seems to accelerate slower or with less power, and then WOT it seems fine.

I have recently replaced spark plugs and fuel filter and it made no difference at all, if anything, it is more noticeable.

It doesn't throw any codes either.

Just throwing it out there but I've read some posts where descreening the MAF has casue various gremlins, especially with the auto tranny.

When did you descreen the MAF? Did the problem follow that? Even though you MIL is not on, still get the ECM read for codes. Possibly still has a code or two with no MIL.

Autozone can pull codes for you, but you will have to look them up yourself... If you do have any codes thrown... look here under your year car.

Gearchatter.com

had a couple of buddies have this problem, myself included. these cars have a tendency of fuel pumps going out, nothing major and you can replace it yourself. If I were you, i'd make sure first that I was getting spark, then second check the pressure at the fuel rail.

I've been troubleshooting a similar problem in my track car. Its a 944 Porsche, but I'm running an LS1 out of an 01CamaroSS. My problem was hesitation at partial throttle as you described. It was good below and above that throttle position. I recently got it working 100% again. The last two things I cleaned/checked are as follows: I took out the MAF sensor (still has screen) and used electronics aerosol cleaner to spray the elements. This was just to make sure the MAF was clean. Then i replaced the plugs. The old plugs (ACDelco) had .070" gap, whereas the new plugs i bought (again ACDelco) are supposed to be gapped at .040". After this MAF and plugs work, the engine hesitation was gone at partial throttle. I know my car is a lot different than most stock LS cars, but I hope this helps somebody.

Quote:

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Originally Posted by thearborbarber

Just throwing it out there but I've read some posts where descreening the MAF has casue various gremlins, especially with the auto tranny.

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i've never had a problem with mine... :dunno:

Something else to look at is the throttle postion sensor but you will need a scan tool.Tps sensors are bassically a rotary potentiometer that varies ouput based on postion may have a bad spot. Or like the other guys say about the maf screen and having gremlins.