Couple issues with 350TBI... related? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TwoFiftyShifter · 01-18-2010, 05:44 PM

My 87 has the 5.7 TBI motor, and has a couple issues.... first the idle fluctuates alot of the time, 500rpm-900rpm and so on, I think it's the intake gasket. However, the truck is either burning or leaking oil. I burnt a quart in 50 miles today.... this happened tihs summer, anjd I got underneath and tightened the oil filter more (probably too much) and its held oil since. I changed the filter lip too, so that's not the issue.... It isnt smoking like crazy, it doesnt leave any puddles on the ground, I just want to know what it could be.

68c10burb · 01-18-2010, 06:04 PM

some sort of vacuum leak would be my first guess, so intake gaskets may very well be it.

does it run fine everywhere else?

TwoFiftyShifter · 01-18-2010, 06:15 PM

Yes and I drove it 2.5 hrs last week all highway and got 15mpg....

chevymotocross · 01-18-2010, 06:56 PM

I would do obvious checks for vacuum leaks. Also, do the testing procedures for the IAC. Maybe reset the IAC as well.

SBTork · 01-18-2010, 07:13 PM

Intake or throttle body leaking vacuum for the first one. Secondly, I would check you pcv system. Check the pcv valve, the tube from it to the throttle body, and so on.

01-18-2010, 05:44 PM	#1
TwoFiftyShifter Registered User Join Date: Nov 2008 Location: Gwinnett GA Posts: 1,803	Couple issues with 350TBI... related? My 87 has the 5.7 TBI motor, and has a couple issues.... first the idle fluctuates alot of the time, 500rpm-900rpm and so on, I think it's the intake gasket. However, the truck is either burning or leaking oil. I burnt a quart in 50 miles today.... this happened tihs summer, anjd I got underneath and tightened the oil filter more (probably too much) and its held oil since. I changed the filter lip too, so that's not the issue.... It isnt smoking like crazy, it doesnt leave any puddles on the ground, I just want to know what it could be. __________________ 1982 K10 SWB 1987 V20 - Sold - Doh!

01-18-2010, 06:04 PM	#2
68c10burb Registered User Join Date: Sep 2009 Location: milwaukee, wi Posts: 9	Re: Couple issues with 350TBI... related? some sort of vacuum leak would be my first guess, so intake gaskets may very well be it. does it run fine everywhere else?

01-18-2010, 06:15 PM	#3
TwoFiftyShifter Registered User Join Date: Nov 2008 Location: Gwinnett GA Posts: 1,803	Re: Couple issues with 350TBI... related? Yes and I drove it 2.5 hrs last week all highway and got 15mpg.... __________________ 1982 K10 SWB 1987 V20 - Sold - Doh!

01-18-2010, 06:56 PM	#4
chevymotocross Registered User Join Date: May 2007 Location: East Haven, CT Posts: 882	Re: Couple issues with 350TBI... related? I would do obvious checks for vacuum leaks. Also, do the testing procedures for the IAC. Maybe reset the IAC as well. __________________ 87 Chevy 2wd SWB: 305/700r4 Dual Exhaust, K&N Filter, Injector Pod Spacer, TBI Spacer, Belltech Front Sway Bar, Corvette Servo, Western Chassis 4/6 and c-notch

01-18-2010, 07:13 PM	#5
SBTork Garage wrench Join Date: Feb 2008 Location: LaCrosse, WI Posts: 1,855	Re: Couple issues with 350TBI... related? Intake or throttle body leaking vacuum for the first one. Secondly, I would check you pcv system. Check the pcv valve, the tube from it to the throttle body, and so on. __________________ -Adam 90 V1500 GMC Suburban 350/700R4/NP241..... 01 Saturn SL1 stock DD.....

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