MAP/TPS/IAC
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Joined: Feb 2012
Posts: 142
Likes: 1
From: North Carolina
Car: 88 IROC Clone
Engine: 305 TBI
Transmission: Auto
MAP/TPS/IAC
Can someone please help me? I have done all that I know to do.
My car had been sitting for about 8 years. Well, I put fresh gas in it and one of the injectors was not firing. Well, the tbi caught on fire so I got another one. Put it on and got it running…..but not well. So, I have changed out all of the sensors that I can think of and it runs like crap. It idles up/down, then shuts off. Now, if I unplug the vacuum line from the map sensor it will idle real well but won’t accelerate. I have tried 2 different map sensors, put on a new tps, iac, pcv and 2 different map sensors. I have looked for vacuum leaks but could not find any. I don’t know what else to do.
Please help!!!
By the way, my car is an 88 it’s a 305 TBI auto transmission.
My car had been sitting for about 8 years. Well, I put fresh gas in it and one of the injectors was not firing. Well, the tbi caught on fire so I got another one. Put it on and got it running…..but not well. So, I have changed out all of the sensors that I can think of and it runs like crap. It idles up/down, then shuts off. Now, if I unplug the vacuum line from the map sensor it will idle real well but won’t accelerate. I have tried 2 different map sensors, put on a new tps, iac, pcv and 2 different map sensors. I have looked for vacuum leaks but could not find any. I don’t know what else to do.
Please help!!!
By the way, my car is an 88 it’s a 305 TBI auto transmission.
Last edited by gsxrfann; Apr 15, 2023 at 06:58 PM. Reason: More info
Supreme Member

Joined: Jul 1999
Posts: 1,556
Likes: 28
From: Adrian, Mi, USA
Car: 1988 Pontiac Firebird Formula
Engine: 5.7 TPI
Transmission: 700R4
Re: MAP/TPS/IAC
Check for vacuum leaks again. Especially the line going to the MAP.
How do the cap/rotor/wires/plugs look?
How do the cap/rotor/wires/plugs look?
Thread Starter
Member
Joined: Feb 2012
Posts: 142
Likes: 1
From: North Carolina
Car: 88 IROC Clone
Engine: 305 TBI
Transmission: Auto
Re: MAP/TPS/IAC
The wires look decent. The line from the TBI to the MAP is good. There is plenty of vacuum on it. That is one of the things that I am confused about. I guess that is the correct one. Is that line supposed to go from the TBI to the MAP?
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Joined: Sep 2002
Posts: 253
Likes: 25
From: honolulu
Car: '86MCSS
Engine: 396 .030"
Transmission: M20
Thread Starter
Member
Joined: Feb 2012
Posts: 142
Likes: 1
From: North Carolina
Car: 88 IROC Clone
Engine: 305 TBI
Transmission: Auto
Re: MAP/TPS/IAC
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Joined: May 2015
Posts: 1,765
Likes: 286
From: Florida
Car: 1991 Z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3:42 Auburn
Re: MAP/TPS/IAC
Check for fuel starvation. I had a 89 Chevy truck with a 350 TBI that ran like crap, would not accelerate and it ended up being the fuel filter. It was clogged and starving it for fuel. I didn't see where you checked/changed the filter or checked your fuel pressure @ the TBI
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Been out of the game far too long. Having a service manual for your car is a BIG help. 