Re: 2000 Pontiac Grand AM GT Loses Power On Acceleration

"jeff1cc" wrote: > I have a 2000 Pontiac Grand AM GT and when I accelerate, it > does not respond well. Also, when I'm at highway speed and
> speed up a little, it accelerates up and down, irregularly. I > have no warning lights, I've had the fuel injectors cleaned > and replaced the fuel filter. I have also replaced the spark > plugs. Any ideas on what it may be?
My guess would be the throttle position sensor.
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"bonne" wrote: > My guess would be the throttle position sensor.
Also check for loose or leaking air duct between MAF sensor and throttle body. Inpect Oxygen sensor for silicon contamination from fuel, or use of improper RTV sealant. The sensor may have a white, powdery coating and result in a high but false signal voltage (rich exhaust indication). The ECM will then reduce the amount of fuel delivered to the engine, causing a severe driveability problem.
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"bonne" wrote: > Also check for loose or leaking air duct between MAF sensor > and throttle body. > Inpect Oxygen sensor for silicon contamination from fuel, or > use of improper RTV sealant. The sensor may have a white, > powdery coating and result in a high but false signal voltage > (rich exhaust indication). The ECM will then reduce the amount > of fuel delivered to the engine, causing a severe driveability > problem.
I take it this has the 3400 engine....how many miles on it? These engines have been prone to intake gasket leaks..and some are pretty bad.
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"autotek27" wrote: > I take it this has the 3400 engine....how many miles on it? > These engines have been prone to intake gasket leaks..and some > are pretty bad.
Thanks for the advice! I did have a severely leaking lower intake manifold leak on both sides. I replaced the upper and lower gaskets and fixed that problem...However, when I put her all back together, Im coming across another problem.
I took it for a test drive, and it didnt have the large surges that it had before (assume it was because Im not loosing vacuum from the intake). When the car warmed up, and I attempted to speed up (in a passing scenario) it wouldnt respond. I could put the pedal to the floor, and it was just creep up, very slowly.
Also, when it was cold, it would idle at around 500-700 RPM...but when it warmed up, it jumped to 1500RPM for idle.
I did get a check engine light a couple times and the error code was to check the TPS. I checked the TPS with my Volt Meter a few times, per the instructions, and came back with good results.
I have also checked the vacuum on the PVC valve, and it seems to be going ok.
It has brand new spark plugs, as of a month ago, and I changed the spark plu wires last year...
Im really stumped...any ideas?
Thanks a bunch!
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"jeff1cc" wrote: > Thanks for the advice! I did have a severely leaking lower > intake manifold leak on both sides. I replaced the upper and > lower gaskets and fixed that problem...However, when I put her > all back together, I'm coming across another problem. > > I took it for a test drive, and it didn't have the large > surges that it had before (assume it was because I'm not > loosing vacuum from the intake). When the car warmed up, and > I attempted to speed up (in a passing scenario) it wouldn't > respond. I could put the pedal to the floor, and it was just > creep up, very slowly. > > Also, when it was cold, it would idle at around 500-700 > RPM...but when it warmed up, it jumped to 1500RPM for idle. > > I did get a check engine light a couple times and the error > code was to check the TPS. I checked the TPS with my Volt > Meter a few times, per the instructions, and came back with > good results. > > I have also checked the vacuum on the PVC valve, and it seems > to be going ok. > > It has brand new spark plugs, as of a month ago, and I changed > the spark plu wires last year... > > I'm really stumped...any ideas? > > Thanks a bunch!
About 8 months ago I was having the same problem. My head ended up having a small crack in it. It would run fine until puching the gas and then it would kind of stutter. I hope its not that but just an idea maybe worth looking checking out. Good luck...
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