misfire/backfire 92 bonneville se 3800
 

Im having a misfire backfire prob with my bonneville. Its been doing this since I bought it and I havent been able to figure out what it is. I think it may be my fuel lines but im not sure i was also thinking about having the crank sensor replaced but if that was bad I dont think it would run. Its not the ignition modle or coil packs, I already replaced those. I found a NOS kit, Performance computer upgrade (programmable by laptop) and a new ignition system that will do nicely but I dont want to put any of that on till I find out what the problem is. The computer isnt throwing out and service codes either so I was hoping to get some suggestions. PLEASE HELP ME!!! I love this car to death and I want to deck it out but I wont do it till I figure out why its running like this. [b]As soon as you stomp on the gas it sputters and backfires. If its cold it runs a little smoother and if you take off like a sunday driver it does ok to. Any suggestions?

I would take a guess at either the fuel injectors being clogged/worn out or the throttle body being excessively dirty. I assume you have already checked the wires and plugs.............. :wink:

Re: misfire/backfire 92 bonneville se 3800
 

Well all you guys are missing the problem here! Remember MY 92 SE! Remember Im running on 5.5 cylinders & why! Remember the 92 3800 NA is EGRless! :roll: Okay, here's what you do to confirm my suspicions: Do a dry compression check on ALL the Cylinders. What I think you will find is that one cylinder will be considerably lower than the rest. :shock: What this means is that you've got the EXACT SAME problem as me & all other EGRless 3800 owners do: A BURNT VALVE! It took me two months to figure out my miss BTW! :shock:

i hooked up my code reader again because now it is also idleing funny it keeps jumping up and down if you know what I mean and it read code 44 which is lean exaust something i dont have my book on me but i know it was lean exaust. How hard is it to do the valves on the 3800? I prefer to do all the engine work on my car. Also if I am to put major performance parts on the bonne what types of upgrades do I need to do to make sure the engine will handle it. Remember this car now has 210,000 miles now but shes still running strong. One thing I was thinking of doing was purchasing a new engine and building that one up until I have everything I want on it. I found a new one for $1500 and a used one with 80,000 miles on it for $300 what do you suggest?

I know this sounds bad since I like doing all the work on my car but how do you check the compression? :oops: thanx for all your help to. I cant tell you how long I've been looking for a website like this. Thanx everyone.

With that many miles you don't want to do just the heads. If you do the bottom end might not like it. I suggest a total rebuild rather than just the top end.

Thanks for the words of encouragement. My point is 210,000 miles is closer to 300,000 than 100,000. If it were my Bonnie and I wanted to keep it I would go through the engine once and be done with it. :wink:

I agree. The possibilities are endless and the 3800 has a long history that proves it.

Missfire/backfire.
 

I dont know if this will help but i was having the same problem with my 97 pontiac firebird. I put a motor in it from a 96 buick and this is the problem i was having. I tried changing the plate underneath the coilpacks and it solved all my problems. No misfire or backfire and the trouble code went away.

I would hope that after nearly 9 years this problem has been resolved. Plese check the thread dates.