1990 Pontiac Grand Am 1990 Grand Am with loud popping

Tiny
PONTIACSTEVE
  • MEMBER
  • 1990 PONTIAC GRAND AM
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 85,000 MILES
I have a 1990 Pontiac Grand Am, with the 2.5 4 Tech. 85k Miles, and for about. 3 months now, after a trip. When ever I accelerate anything past idling RPM, wich is also abnormally high. I get a very loud popping sound, wich I can almost discribe as a very loud cork being popped out of a wine bottle, coming from the engine bay on the passenger side. And it will do it repeatedly untill I let off the gas, The car has never died while driving or idling just runs rough at a stop light or when parked idling, But in the mornings or when ever the car has sat for more than 12 hours, it is very hard to start up, if at all. I usualy have to wait a few hours to try and start it, and usualy starts up like nothing happened. Leading me to belive it gets flooded, wich goes with the high idling, the gas might just be seeping into the cylinders slowly as it sits. Anyway back to the popping, When driving like I said if I give it anything over just touching the gas pedal, it pops repeatedly and slows down. Any help with this will be greatly apreaciated. Thank you
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Friday, June 12th, 2009 AT 3:05 PM

3 Replies

Tiny
MERLIN2021
  • EXPERT
Is your service engine light on or flashing? I would check the timing and plugs and plug wires, you are out of time, or plug wires are shorting out and it may be backfiring through the intake. Or you have a worn cam or bad intake valve. Compression test will reveal that.
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Friday, June 12th, 2009 AT 5:32 PM
Tiny
PONTIACSTEVE
  • MEMBER
Yeah the check engine light comes on when I idle in park or at stop lights, not when im driving. And I am hoping it isnt my cam, cause I can't afford that lol.
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Friday, June 12th, 2009 AT 9:03 PM
Tiny
MERLIN2021
  • EXPERT
RETRIEVING CODES (NON-SCAN) 1. Turn ignition on. Do not start engine. SERVICE ENGINE SOON light should glow. Locate Assembly Line Data Link (ALDL) connector attached to ECM wiring harness. Most ALDL connectors are located under dash on driver's side of vehicle. For exact location of ALDL, see appropriate COMPONENT LOCATIONS illustration in SYSTEM/COMP TESTS article. Turn ignition on. Insert jumper wire from terminal "B" (diagnostic test terminal) to terminal "A" (ground) of ALDL connector. See Fig. 1 . Fig. 1: ALDL Connector Terminal Identification Courtesy of GENERAL MOTORS CORP. 2. SERVICE ENGINE SOON light should begin to flash codes. Each code will be repeated 3 times. If codes are not flashed, perform DIAGNOSTIC CIRCUIT CHECK in BASIC TESTING article. To exit diagnostic mode, turn ignition off and remove jumper wire from ALDL connector. NOTE: Inserting jumper wire into test and ground terminals of ALDL connector with engine running will cause fuel injected vehicles to enter field service mode. Codes will not flash if this is done. See FIELD SERVICE MODE in BASIC TESTING article.


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Sunday, June 14th, 2009 AT 12:10 PM

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