98 century 3100 v6

Asked by Mar 17, 2016 at 03:03 PM about the 1998 Buick Century Custom Sedan FWD

Question type: General

Just replaced the intake manifold gasket on my
Buick century 3100, and now I'm having problems
with the idle and with it running. It's not wanting to
go into high revs, and at idle it runs rough. I keep
getting a MAF sensor reading and a general misfire
reading, but I replaced the MAF and it didn't fix the
problem. Any ideas on what's causing this?

6 Answers


Double check your vacuum lines. A manifold vacuum leak can cause symptoms similar to what you are describing and you would have removed some to do the gasket change.

I've got all the vacuum lines reconnected and none of them seem like they're leaking. My throttle position sensor put up a code, so I'm wondering if it isn't that. If it isn't, how can I get the butterfly valve to open with the throttle?

It operates fine if we manually play with the throttle cable, but at an idle it's running really rough and under load it won't accelerate past 2k rpm


Adjust the cable, maybe?

That's what I figured but it wasn't tampered with enough to need to be rearranged


Check to see if the spring inside the throttle position sensor (TPS) is broken - you will need to take it off the throttle body to do so. It will be obvious when you move the "D" shaft on the back plate of the sensor, and it provides no resistance. If the spring is broken, the TPS will not correctly note the position of the throttle plate, and subsequently send an incorrect signal to the cars computer. This will cause issues including those you have noted.

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