Running Rough!

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Jun 25, 2004 | 07:36 PM

the-last-resort

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From: Spring Hill FL

Running Rough!

Where to go next, Changed plugs,wires,cap, rotor,fuel filter,sock on fuel pump,air filter,pcv valve,cleaned throttle body and air passage from filter. I know the car is capable of power, It hauls butt whenever it decides to but for the most part it`s bogging down. Car runs so bad that the idle sounds like it has a radical cam but I know better. Are there any sensors or some other suggestions I`m missing- 86 L98 auto. Thanks in advance for advice.

Jun 25, 2004 | 08:37 PM

65Z01

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From: SE NY

Cruise-In II Veteran

Re: Running Rough! (the-last-resort)

Check base timing, if too low it will tend to be rough and not responsive.

Check the EGR valve for leakage and clean the IAC as either can lead to rough idle.

Also, set base idle to 450rpm and advance the TPS base setting to .65Vdc for a little better throttle response.

You might also check for vacuum leaks as these will lean out the charge at WOT with resulting loss of power.

Jun 25, 2004 | 11:38 PM

vettenut85

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From: machesney park il

Re: Running Rough! (65Z01)

my 85 idled like a radical cam once,turned out to be leaking fuel injectors.

Jun 26, 2004 | 10:37 AM

the-last-resort

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From: Spring Hill FL

Re: Running Rough! (65Z01)

Thanks for the advice,I`ll try them in that order. Is the IAC cleaning a difficult job, I read somewhere that you could ruin the "pintle" ? Can any or all of these suggestions attribute to occasional running great-Like I said sometimes the car feels like it wants to pull hard but other times it will bog. Thak again for your advice.

Jun 26, 2004 | 11:29 PM

Vett-eight-nine

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From: Toronto ON

Re: Running Rough! (65Z01)

"Also, set base idle to 450rpm and advance the TPS base setting to .65Vdc for a little better throttle response."

I'll preface this by saying I'm no expert, but I read that a technical service bulletin suggested raising base idle to 550. I just set mine to 550 today...

Jun 27, 2004 | 12:49 AM

skateparkdave

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Joined: May 2004

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From: Lufkin Texas

St. Jude Donor '05-'06

Re: Running Rough! (Vett-eight-nine)

I had a fuel injector on my 90 that was only working part time and caused near symptoms your describing.

Are you getting any codes??

Jun 27, 2004 | 11:20 AM

the-last-resort

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From: Spring Hill FL

Re: Running Rough! (skateparkdave)

Previous owner replaced injectors before I bought it. Have not checked for codes and am unsurehow to advance the TPS setting? A lot of the remedies I have no knowledge in so I`m trying to learn a little at a time. I`ve been burned too many times at the repair shop so I`m trying to do the most I can myself.

Jun 27, 2004 | 11:36 AM

Chevy Guy

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From: NJ

Re: Running Rough! (the-last-resort)

You have to narrow down your search a bit, dont just throw parts and money at it. It could literally be anything from a bad plug to a broken valve spring to a ECM. Have it diagnosed properly first. Try and narrow it down to spark, fuel, a particular cylinder, etc etc...... Trying to fix it blind will end up costing you much much more than bringing it to a shop.

[Modified by Chevy Guy, 4:37 PM 6/27/2004]