my buick start good even by -25 celcius but once it started it hesitate and even backfire trought the trottlebody,once it is at normal operating temperature it run good ,exept going uphill at 30mph it kick and backfire.this past week i,ve been at it.The ses light dont come on so there is no code.first i changed the spark plugs,no change,i put new wires (they were lifetime garanteed)nothing,fuel pressure is at 30(should be ok ?),took all the injectors off and cleaned them +cheked for any off them leaking,no problem there,I checked the coils i readed that checking resistance between two coil and comparing all off them there should be no difference two didnt have the same reading so Ichanged the coil pack,still no change,02 sensor gave me reading of lean and rich mixture,I assume it's ok,took the egr out, took it appart and tested it,work good,so i changed the pcv valve,a mecanic told me the magnet on the timng chain could break or fall off and timming chain could be due at 185000k,so tookit apart,put a new magnet(it looked broken)and new binder was worn out, but timing chain and gears .were ok.thats where I'm at now ,and still no change.anybody could help me please,I never took this car to a garage but this time I guess I have no choice.

Fuel should be 45Psi.. and have GOOD FLOW.
Check ignition module..
Check for BLUE HOT SPARK not just yellow.
Test the volume flow of the fuel pump. Sometimes they start flowing strong and quit after a little time.
Bad pumps work some but not on hills. They have not enough volume flow..
Pumps will not give codes ever, I believe.

Good Luck.



Edited by: bassasasin

thanks i,ll be checking that tomorow

The backfiring is more like ignition cutting in and out.. however. .

Good Luck

so I did check.Ihaad 2 other fuelpump from previous car I dismantled.I bypassed the fuel circuit and connected a line directly in the fuel line from a fuel pump Ihave put in a gallon full of gasoline,the fuel pressure went to 45 psi right away,and went for a ride around the block,the ran fine,when Icame back,my gallon of fuel was empty.So Iundid the fuel return line and instaled one with a clear hose back in my fuel gallon.When I started the car I could see the gas going back in my fuel gallon.So i hooked back the line from my gas thank,started the car,the fuel pressure was low and the fuel did not return trough my clear return line in my gallon.So i toof down the gas tank and changed the fuel pump.Car is running good so far (only drove it a few miles)but Iguess my problem is solve.


If bassasasin read this thank's man your advise helped me a lot,more it gave me confident in continuing my search to fix that car I was outpassed by these problems and was going to take the car to the garage tomorow (it would have seen a garage for the first time since I ownthat car ,about ten years now.

Yes.. I read .. thanks for response.. often a fixed member just dropps off the forum.. and drives away..without responding.

You made my day today.
PS.. never let the car run out of gas.. it burns up the pumps.
Buicks that have bad symptoms in hot weather sometimes ends up being the fuel pump failing at about 95 outside.


Bassasasin