My 92 GMC 1500 Automatic runs strong from a stop in 'Open Loop'. In "Closed Loop' it runs very lean, low power and stuttering. If I keep my foot in it, at about 2500 RPM it pulls strong again.


Asked by Mar 09, 2015 at 12:08 AM about the 1992 GMC Sierra 1500 C1500 SLE Standard Cab SB

Question type: Maintenance & Repair

I have replaced the O2 sensor, MAP sensor, TPS, EGR valve, plugs, wires, cap & rotor. I measured the Temp sensor & its in range cold & hot. I also added a performance chip to the ECM. If I disconnect the temp sensor once warm, it goes rich and will die at idle as expected. At idle the O2 sensor voltage swings from 0.1 V to 0.8 V. I tried adding a 780 Ohm resistor to the Temp sensor ckt, it will raise the idle and lower the strong pull to about 2000 RPM but it bogs even worse when initially flooring it. If it were fuel pressure, it wouldn't pull strong above 2500. BTW the old plugs were clean, a light tan colored insulator.

1 Answer


Turns out I was wrong about it being lean. One injector was leaking. I disconnected one injector at a time. On the good one it would hardly move the truck, but on the leaky one it ran almost normal. a new injector fixed it.

Your Answer

Add photo

Related Questions

  • rough idle, stalling, loss of power. 225 answers

    o2 sensor code 44 (lean) Replaced: coolant temp sensor, tps, map sensor, fuel filter, and o2 sensor. It will run normal on occasion but only lasts about 45 seconds or so. I don't think its the torqu...

    1995 GMC Sierra 1500 K1500 SL 4WD Extended Cab Stepside SB


    Maintenance & Repair

  • Stalling out and wont stay running. Acts like it wants to run but gets choked out. 45 answers

    I have a similiar problem as devin, my 95 Sierra 4x4 it has a 350 5.7L engine and the fuel filter has been replaced I cleaned the injectors out and put a new gasket on. The shop said I have good fuel ...

    1995 GMC Sierra 1500


    Maintenance & Repair

  • started stalling and dying when in gear 89 answers

    350 motor 4L60E trans Motor wants to stall while in gear (but doesn't do it out of gear once over 1000 rpm it dosent) seem to stall and it is only from a dead stop. Fuel filter has been replaced an...

    1994 GMC Sierra 1500 C1500 SLE Extended Cab SB


    Maintenance & Repair

  • 98 gmc k1500 5.7 manual trans will start missing during driving when the shift light comes on? Why? 13 answers

    I have changes the plugs, wires, cap and rotor button, also changed tp sensor. The truck does not miss when just setting and idling or even Revving it up, only during driving, notice it will star...

    1998 GMC Sierra 1500 K1500 SL 4WD Extended Cab LB


    Maintenance & Repair

  • I need help with a 1993 gmc 5.7L tbi. 24 answers

    Ok, so i have a 93 gmc suburban. I just put a new engine in. It has flat top pistons running about 9.2 to 1 compression and an rv cam. The truck itself has about 282000 miles on it. I am having an...

    1993 GMC Suburban K1500 4WD


    Maintenance & Repair

Search GMC Sierra 1500 Questions

GMC Sierra 1500 Experts

#1 dragonflyoffshore
Reputation 4,410
#2 John Saffrahn
John Saffrahn
Reputation 3,080
#3 Glenn Clingenpeel
Glenn Clingenpeel
Reputation 2,700
View All

Related Models For Sale

Used Ford F-150"
3,268 Great Deals out of 216,650 listings starting at $1,500
Used GMC Yukon"
563 Great Deals out of 19,457 listings starting at $2,500
Used GMC Sierra 2500"
223 listings starting at $2,895
Used Chevrolet Camaro"
797 Great Deals out of 38,852 listings starting at $2,650

Used Cars For Sale

2017 GMC Sierra 1500 For Sale
20,104 listings starting at $20,851
2016 GMC Sierra 1500 For Sale
75 Great Deals out of 13,158 listings starting at $21,510
2015 GMC Sierra 1500 For Sale
192 Great Deals out of 4,739 listings starting at $15,995
2014 GMC Sierra 1500 For Sale
147 Great Deals out of 4,295 listings starting at $12,500
2013 GMC Sierra 1500 For Sale
95 Great Deals out of 2,678 listings starting at $12,400