High Idle and No 4th gear

Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's, Olds 98 91-96, Buick Lesabres and Park Avenue 91-96. Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.
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aklbeach
LE Member
Posts: 3
Joined: Thu Feb 27, 2014 2:25 pm
Year and Trim: 1994 SSE 211,000

High Idle and No 4th gear

Post by aklbeach »

I have recently and many times replaced the TPS and it usually fixes the problem. But the car in drive idles really high to the point it really wants to take off if you don't hold the brake down. It also will not shift in to over drive on the highway. I also replaced the throttle body gasket about a year ago. Should I try the Idle air control valve next? How does the car act if you unplug the TPS and the idle air control valve is bad?
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bad.moshi
SSEi Member
SSEi Member
Posts: 165
Joined: Thu May 22, 2008 9:52 am
Year and Trim: 1993 Bonneville SE
Location: Maryland

Re: High Idle and No 4th gear

Post by bad.moshi »

It acts awful. Unplugging the TPS shoudn't change much... Sadly, I drove my car for months without it connected. I lost MPG, Cruise control (that I don't use) and had to deal with a SES light, but that's basically it. A few minor issues with feathering the pedal at slow speeds...

Anyway, with a bad or unplugged IAC it will act really strange... surges and stumbles, the car doesn't know how to handle itself. At least that's how mine acted when I unplugged it as a diagnostic.
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Bonneville SE -- Cruising the mountains, surfing the lowlands, and passing broken down competition since 1993!
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