Surge & Sputter, Rough Idle Continuous Problem

S

scw7080

scw7080
Joined
May 10, 2010
I own a 1987 Grand National and when I start it cold it idles decent for the first 20-30 seconds. Then the engine surges, sputters, and continues to do this 4 or 5 times. Sometimes the engine even stalls. In fact, if you start it cold and immediately take off driving the engine will stall. This is not a problem when the engine is warm. Also when you step on the accelerator there feels to be a split second lag.

The spark plugs, spark plug wires, throttle position sensor, air control valve, MAF, and oxygen sensor are all new and work fine. Alternator and fuel pump work fine as well and mechanic cannot find any problems with the computer.

I am at my wits end regarding this problem for more than one dealer and mechanic have tried to repair the problem and cannot do so for they cannot find anything wrong. Please help. Thanks.
 
Have you checked the coolant temp sensor? It could be sending false temp reading. Haven't had this problem or seen this on our cars but have on lots of other GM's. Temp sensor gives false temp reading and causing fuel enrichment issues. Just a thought.
 
scw7080 said:
I own a 1987 Grand National and when I start it cold it idles decent for the first 20-30 seconds. Then the engine surges, sputters, and continues to do this 4 or 5 times. Sometimes the engine even stalls. In fact, if you start it cold and immediately take off driving the engine will stall. This is not a problem when the engine is warm. Also when you step on the accelerator there feels to be a split second lag.

The spark plugs, spark plug wires, throttle position sensor, air control valve, MAF, and oxygen sensor are all new and work fine. Alternator and fuel pump work fine as well and mechanic cannot find any problems with the computer.

I am at my wits end regarding this problem for more than one dealer and mechanic have tried to repair the problem and cannot do so for they cannot find anything wrong. Please help. Thanks.
Click to expand...
What chip are you using? If it is the stock chip, they are known for their horrible idle characteristics. Scanmaster numbers? Is the car completely stock?
 
Sorry to bring the thread back but i am havin the EXACT same problem and was wondering if a solution was ever figured out
 
Did it just start out of the blue or has it always been this way? What have you tried so far? Whats done to the car?
 
My car has been doing it for a while, I havent had time to mess with it but I am changing all of the vacuum hoses and my turbo to MAF hose this weekend because the BLMs are high... The only mods are a dual exhaust with no cat and a 160* thermostat
 
Im thinking that it could be the idle air control valve... Worthy suspicion?
 
Have you checked out the site: http://www.vortexbuicks-etc.com/troubshootgeneral.htm? It has LOTS of good info on it. Also, you would need a tester made by Caspers I think. When mine started acting weird ignition wise, I bought a TR6 from Bob Bailey. The ability to use it for troubleshooting made the purchase a no brainer for me.

But back to your problem. Once you change all the hoses, check your fuel pressure, O2 sensor, MAF (especially), intercooler hoses, Headers/gaskets, etc. Then post up what your scanmaster numbers are on every item which might clue someone in. What are the O2 numbers when this happens? What are the high BLM's? What does the IAC number look like? Post it all and we can figure it out.
 
Crazi said:
Have you checked out the site: http://www.vortexbuicks-etc.com/troubshootgeneral.htm? It has LOTS of good info on it. Also, you would need a tester made by Caspers I think. When mine started acting weird ignition wise, I bought a TR6 from Bob Bailey. The ability to use it for troubleshooting made the purchase a no brainer for me.

But back to your problem. Once you change all the hoses, check your fuel pressure, O2 sensor, MAF (especially), intercooler hoses, Headers/gaskets, etc. Then post up what your scanmaster numbers are on every item which might clue someone in. What are the O2 numbers when this happens? What are the high BLM's? What does the IAC number look like? Post it all and we can figure it out.
Click to expand...
Ok thanks, i'll check that out and look into a testing
 
You must log in or register to reply here.

Similar threads

D
runs with stock ecm, not with xfi 2.0
2
Replies
20
Views
758
DGC
D
8
Turbo t electric problem
Replies
15
Views
1K
87GNTURK
8
C
TR6 problem.
Replies
3
Views
711
Clark6
C
C
TR6 problem.
Replies
3
Views
485
chadswe4
C
H
GREMLIN CONTINUES TO BE PRESENT MAKING DRIVING UNSAFE
2
Replies
29
Views
1K
Ttype6
T
Top