GM fuel injection problems

[Sonny Raye]

I read other's notes regarding possible GM fuel injection problems. The fellow who was visiting in Aurora, IL, described my situation exactly. Rough, knocking, start up sound, followed by flashing check engine light. Car is very rough for quite awhile, but then smooths out.
Go to dealer, dealer wants lots of money to clean injectors, which have now been done 3 times this year. Dealer blames bad fuel, but have follow his advice, using only premium, and switching makers every tank, but using Shell V-Power about 50 % of time.

The knocking sound at start up is solid metalic, like a metal bar going back and forth on top of a huge alarm clock. Not tinny.

One other thing. I noticed before all this started, that the engine idle was not higher at cold start. it stayed under 1,000 rpm.

I have a 96 Buick Regal, with 51 K miles. This just started in the last 12,000 mi, and never happened before. I have the larger 6 cyl engine, not the 2.8 l. All service is done regularly.

I think something is broken, or there is some flaw. Any help?

Sonny

[QuasarCav]

Piston slap?

does the sound go away after driving for a while?

2.8 hasn't been used in ages, I'm guessing you have the 3800.

[Sonny Raye]

Hey, Alberta,
Thanks for the reply.
Yes, the klunking sound goes away as soon as the idle roughness smoothes some, about 2 minutes or so. I noticed that every time I backed out to the right I would hear the sound, but only when the engine idle was still a little rough. All went away once the engine stopped running rough, but the C E light changed from flashing to steady.
This has been irritating because once the initial problem presents, and if I can't get to the dealer right away, the C E light stays on, but the car runs fine. It has only happened at start up, usually after the car has been driven once that day, then left alone for an hour or more.
Sonny

[gtkane]

Sonny

I am a GM tech and am familiar with this problem.
It sounds like you have a 3100 or 3400 V6 with piston slap as Quasarcav said. GM knows about this problem and will rec. new pistons.THIS WILL NOT FIX IT.
the noise will come back in 20-30k
The good news is the noise is not damaging anything if it goes away in 3 min.
The check engine light flashing usually indicates a misfire(code P0300). Take your plug wires off of your coils and you will probably find one or more terminals that are rusty.Replace those coil(s) and corresponding wires and it should run like new(knocking aside)

Graham