Backfire when hitting throttle from idle,need help.
Thread Starter
Intermediate
Joined: Jul 2018
Posts: 48
Likes: 5
From: Central Maine
Backfire when hitting throttle from idle,need help.
Hi all ,i would appreciate some help with my problem.
Bought this '92 LT1 with 133k miles on it in overall great shape,last year.
Couple of weeks ago i woke it up from it's winter snooze and replaced all 7 coolant hoses since they were original,pulled knock sensors and cleaned up the pressure and overflow tanks.
Also replaced the pulley on belt tensioner cause the bearrings were starting to make noise.
Problem im having is when i hit the accelerator while parked it will stumble and backfire.
Once it accelerates and you keep revving above 1.5-2k rpms it's smooth.
Last summer while highway cruising i had an EGR code come on a couple of times and i know i need to look in to that.
Is it likely perhaps a stuck EGR valve is causing the backfire/stumbling? dont think it's opti related at least i hope not since tach is reading normal.
The car was stored with non ethanol premium gas with stabil and i had a battery tender on it all winter.I also started it every month ,warmed it up reved it and made sure the engine came up to operaring temp.
Any ideas as to where to start will be great,i'm going to fix the EGR problem and hope it cures the problem but i'm open to your input,thanks.
Bought this '92 LT1 with 133k miles on it in overall great shape,last year.
Couple of weeks ago i woke it up from it's winter snooze and replaced all 7 coolant hoses since they were original,pulled knock sensors and cleaned up the pressure and overflow tanks.
Also replaced the pulley on belt tensioner cause the bearrings were starting to make noise.
Problem im having is when i hit the accelerator while parked it will stumble and backfire.
Once it accelerates and you keep revving above 1.5-2k rpms it's smooth.
Last summer while highway cruising i had an EGR code come on a couple of times and i know i need to look in to that.
Is it likely perhaps a stuck EGR valve is causing the backfire/stumbling? dont think it's opti related at least i hope not since tach is reading normal.
The car was stored with non ethanol premium gas with stabil and i had a battery tender on it all winter.I also started it every month ,warmed it up reved it and made sure the engine came up to operaring temp.
Any ideas as to where to start will be great,i'm going to fix the EGR problem and hope it cures the problem but i'm open to your input,thanks.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Backfire when cracking throttle many times is lean condition. Fix EGR first. Tune up may help, scanner monitoring MAP, it should respond instantly with throttle. O2 and INT/BLN Make sure all are clicking; 93 LT1 pulses 4 injectors at a time. It can idle on 4 if 1 of the 2 fuses blows.
