ENGINE DIES ON BACKING OUT

[Mica]

Good day to everyone and thank you in advance for the help. I have 1990 Astro van V6-4.3L RWD 316828 miles with no major issues.
This year the van did no pass smog check. I replace the catalytic converter, EGR valve and O2 sensor to pass. Soon after I notice irregular RPM drop at engine stop. After to or three months at backing out, engine will shudder. Soon after that any time I back out, or park the van, turning the stirring wheel to the stop, engine dies. I have replace idle are control valve(IAC) and throttle position sensor(TPS), vacuum lines and EGR valve are new.I have used the stethoscope to check for vacuum leaks. There is no engine light on. Engine ran good for two months and did on me two times. Only dies on backing out, and recently just to start to drive. Please help.
Thank you.

[justice]

when my 1987 Safari was exibiting the same kind of symptoms, it was my fuel pump getting weak.

[Mica]

The fuel pump is fairly new . On old pump I made 250000 mil.
Appreciate your help.

[LiftedAWDAstro]

Pull the EGR off and check for chunks of carbon.

[Mica]

I will check EGR this weekend.
Now symptoms are getting bigger. I stop at the store yesterday,half an hour later I start the van it almost died. I tap the gas pedal the engine recovered. When i got home I turned it off waited for a fifteen minute, started the engine run good, put it in drive started to stall, I put it in park engine recovered. Today everything went good.
Thank you All.
Appreciate your help.

[Mica]

Pulled the EGR today looks good, there is no carbon debris, holding vacuum for a long time, moves freely, it is new. I was thinking to buy ACDelco.This one on the van maybe gets stuck some times.

[Mica]

New fuel pump is on the way.
Thank you All.

[1Gary]

It is likely it's the f/p with that many miles on it if it was never changed before.

I am suggesting a completed bucket check list rather than shotgunning parts at it.

A fuel pressure check should be apart of that list.

That doesn't exclude the possibility of a clogged fuel filter and that should be changed in any event.

The other thing is to have the dog house off running the engine with the air filter off and be looking at the TBI injectors for a nice cone shape spray.

Fuel pressure regulator can be checked by turning on the key listen to the F/P run for about 2 minutes and shut off while looking at the fuel pressure.Then turn off the key and watch the pressure bleed back off.

All grounds to the F/P harness should be cleaned and there is a internal wire harness that should be changed with every F/P replacement.

Less you want to do a "do-over" avoid the cheap F/P's being sold like Airtex.They don't last long.The only company selling OEM spec F/P's is Delphi.As long as you run a 1/4 of a tank gas all the time,you should easily expect another 100,000 miles out of a Delphi.The fuel cools these pumps and to run a lower than 1/4 often will shorten the life of the pump.

Spray the hell out of the tank strap bolts with pen oil aleast twice(acouple of days in advance) and let set to soak in.

Gasoline is heavy.Try to get as much gas out of the tank as you can.Lower and raise back up with a floor jack.Do not get under the tank.

Given the lower pressure of your F/P you should be ok with any splice rubber hose if you need to do that,but better yet is what is known as fuel injection rubber hose and clamps.I double up the clamps so as not to have any problems.Trust me you don't want to drop the tank a second time anytime soon.

If your in the rust belt,while the tank is out take a close look at the brake line running to the rear over the gas tank.Pin holes count and if you can't find a leak,your be tearing your hair out to find it rotted out up there out of sight.

Safely raise the van from both ends on jack stands only.Getting the extra room to work you'll be thank full for as you do this job.

But getting back to my point.Do that bucket check list.It could potentially save you time and money.

[Mica]

Thank you for a thorough explanation and advise. I am gearing up for this weekend.

[Mica]

Changed the fuel pump no problems. Van runs better then ever.
Thank you All for a help.