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1997 Chevy Astro Engine surging on acceleration

Tiny
B717DOC
  • MEMBER
  • 1997 CHEVROLET ASTRO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 16,200 MILES
1997 Astro Van, been a great vehicle for us, and choose to keep her, as dealer will only offer $500 trade in value. She starts and idles sweet, but once you get her out of the driveway, as the RPM'S increase up to the shift level, engine cuts and shudders mildly until she shifts into the next gear. Same with remaining sequence of shifting. I don't believe it's a transmission problem, just seems the engine is having some type of ignition or fuel delivery issue. Once the engine is hot, all is normal. There's no "check engine" light on either. Symptoms VERY pronounced when engine is cold, but dissipate dramatically once engine is hot. Im thinking fuel injectors right off the bat, but really, I have no idea. Plugs, wires, cap and button all new, new fuel pump also. Don't want to be raked over the coals at a repair shop, and am pretty good mechanic, just want to minimize the pain. Thanks, and great site. Mark in Hiram, Georgia.
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Wednesday, March 11th, 2009 AT 11:46 AM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,179 POSTS
Mark, have you tried the basic fuel injector cleaner? Also, the temp sensor may be sending a bad signal to the computer causing it to run too rich or lean. Also, because of the mileage on it, have you checked for an intake leak (somewhat common) and the compression?

Let me know.
Joe
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Wednesday, March 11th, 2009 AT 8:39 PM
Tiny
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Yes, Joe, we have used injector cleaner, sea foam, and additech, all to no avail. There is no "check engine" light on, have not checked compression, or for an intake leak. Does'nt sound like an intake or vacuum leak, as once it gets to temp, she runs much better.A leak would show symptoms at all times, right?
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Thursday, March 12th, 2009 AT 8:13 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,179 POSTS
One would think a leak would always show, but remember, unlike water, when steel gets cold, it shrinks and when it gets hot, it expands which colud eliminate a leak. The same with compression.

It's just a thought because it can happen and I know you have been through a lot already. The 4.3L has had a history of intake leaks, so that is why I suggested it.
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Thursday, March 12th, 2009 AT 1:14 PM
Tiny
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  • 8 POSTS
Rodge. Will pull the doghouse (again) and spray Gumout or something to see if I get an increase in RPM's with the engine cold. She's definitely a sick car.
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Friday, March 13th, 2009 AT 5:59 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,179 POSTS
Some use starting fluid, but remember these things are very flamable and it they hit an area that is hot enough, will flash and cause a fire.
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Friday, March 13th, 2009 AT 10:28 AM
Tiny
B717DOC
  • MEMBER
  • 8 POSTS
Had to replace rear end, as terrible noise coming from van when shifted into gear. Driveshaft turning, but wheels not. Hmmmm. Not good. Pulled rear end cover, lots of metal. LARGE pieces. Went to pull a part, got another rear end and installed, hoping this would maybe fixx my hesitation problem. But no help. Rear end works well, but shuddering very pronounced when engine is cold. If you shift to neutral, engine accelerates very smoothly up to max rpm, but in gear and accelerating, surging VERY pronounced until warm. Tranny or engine?
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Monday, April 13th, 2009 AT 8:14 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,179 POSTS
Sorry it took so long to get back. Had another extended hospital stay for several days. As far as the differential, that sounds as major as it can get. Listen, as far as the engine, you either have a bad vacuum leak, low compression, or lack of fuel under a load.

Sorry, I'm a bit out of it, but did you check all of these items?

Joe
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Tuesday, April 14th, 2009 AT 7:28 PM
Tiny
B717DOC
  • MEMBER
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No, I have'nt had a chance to get the "dog house" off. Had to devote 2 days installing rear end, which by the way, worked out great. I drove the van yesterday after it had been sitting for about a week, and thought it was'nt gonna make it, as the shuddering was worse than ever.I just took it easy on it, and as soon as it warmed up, symptoms dramatically decreased. Thanks for your help and attention, and hope you get to feeling better.
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Wednesday, April 15th, 2009 AT 6:22 AM
Tiny
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  • MEMBER
  • 8 POSTS
Finally got a day to work on her."Service Engine Soon" light on now, but only the "P0137 O2 sensor" fault, which has been with us for years. Pulled plugs, found gap to be ALOT. Book says.060, so replaced them anyway with iridiums. Found #2 plug only held in by a few threads (Thanks Brad!). Sprayed gasoline with windex bottle all over intake while at idle, no increase in RPM, only blood pressure. Ohmed out all plug wires, found okay. Drove around north Georgia with dog house off, man that's hot! Same thing. Shudder disappears after engine runs for awhile. "Service Engine Soon" light went out, right on schedule, as always. Maybe a transmission flush is in order, as engine does not shudder while in neutral increasing RPM.
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Tuesday, April 21st, 2009 AT 10:27 AM
Tiny
B717DOC
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  • 8 POSTS
Decided to check Ignition coil and ignition module, both mounted on same bracket. Took to 4 different auto parts stores, only one could half way test the module, said it was good, then said it was bad, did'nt really know. Go to "pull a part" to get another module, out of 12 AstroVans, Every module already taken. Seems to be a pattern. Will probably bite the bullet an buy one from AutoZone for $62 and hope it fixxes it.
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Tuesday, May 26th, 2009 AT 7:07 AM

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