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Ron, ASE Certified Technician
Category: Buick
Satisfied Customers: 35515
Experience:  34 years as a Tech
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My 97 lasabre began to idle irratickly and within a mile i

Customer Question

my 97 lasabre began to idle irratickly and within a mile i cleaned the iac tps map and even swithed with known good extras when i pulled the intake off it was melted...again. i whent through all this a few years back and got good miles out of it this time around i tried the junk yard intake and sensors withno inprovement codes are for tps and clogged cat did i swap a bad intake manifold and need to find another or is my wife right saying its over
Submitted: 2 years ago.
Category: Buick
Expert:  Ron replied 2 years ago.
Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here If you where not having any idling problem before you replaced the intake then its very likely the used unit is leaking and or warped and not sealing. Try taking some carb cleaner and carefully spraying short burst around the intake are where it bolts on and see if there is any change in the way the engine idles. If there is any type of change then the intake is leaking. Check this an let me know and we can work from there .
Customer: replied 2 years ago.
Hello again Ron I was a bit unclear late last night when i detailed my problem. I learned 5yrs ago about the weakness of some GM intake manifolds an successfully switched the melted manifold as well as sensors (IAC TPS MAF) EGR valve and pressure regulator. 50000 miles approx were drive with only another TPS needed. That all changed last week. A few miles fom home the idle shot to 2000 - 3000. Then a stall and irrattic for a few blocks to where I began the search. A local mechanic pulled a code for cat converter and a few for the TPS. He diagnoised the problem as backed up heat melted the intake. I got the car back not wanting to throw money at an old car that doesnt seem to have a intake system that will keep it on the road reliably. However my plan to sell it to a junk yard is slowed by my curiosity and a few hundred bucks extra if I drive it in vs. towing. So, I bought a junk manifold with a unlimited return for a month warranty. Day two, manifold two, same high idle and TPS code but no cat code. The EGR IAC TPS MAP throttle linkage are clean and appear to check out when testing with spares and wiring is giving me correct values on the multimeter. My next move tomorrow will be putting up cash for autozone sensors starting with the TPS unless you can talk me into a different direction. smashup derby perhaps.
Expert:  Ron replied 2 years ago.
Before you replace anything else can you give me the actual code and or codes your getting?
Customer: replied 2 years ago.
The shop told me the code were for MAF. TPS. And catalic converter. I do not know exact codes but he looked past the throttle body and saw the melted intake. My codes read po122 po122 po101
Expert:  Ron replied 2 years ago.
Before you replace anything run the pinpoint test for the TP sensor in the first link below, Copy and paste the links to your browser to open and view them. the pinpoint test in the link below for the MAF sensor as we.. If either one of these are failing they could very well be your problem.
Customer: replied 2 years ago.
It starts and jumps to 4000 rpms with two different TPS and / or MAF and I tried some tests and they seem to come up normal I will try your links as well as inspecting the wires to the PCM . could a faulty connection at the PCM cause this 4000 rpm startup
Customer: replied 2 years ago.
I believe all vaccum lines are OK. Two different manifolds same 4000 startup. Two TPS. Two MAF. Something started this resulting in the melt down or. Could the melt down have caused a warp or crack I cannot detect that the PCM compensates for with the high idle
Customer: replied 2 years ago.
If the first shop forgot to tell me about an additive to clean the clogged exhaust would that result in such a high idle?
Customer: replied 2 years ago.
I'm looking for clues that may not be easy to find. bad fuel. Bad IAC. Bad TPS. Bad MAF. Bad PMC bad wiring. Bad EGR. Bad linkage. Every bad seems to check out OK. But still a 4000 rpm that will not drop
Expert:  Ron replied 2 years ago.
I would recheck the TP and MAF as well as the wiring , It entire possible you may have a failing PCM as well.
Customer: replied 2 years ago.
Thanks again. I will retest
Expert:  Ron replied 2 years ago.
Your very welcome and thank you as well.

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