Stuttering on acceleration
- Thread starter jmelhuish
- Start date
peanut
Active member
if the running improves when shes warmed up i would look at a fuel issue like sticky injectors . Especially if the car is used infreequently or hasn't been used for a few weeks. Check that all the injectors are clicking strongly by using a screwdriver to your ear if necessary.
Might have some water /imputities in the tank that have seperated if shes been standing a while. Stick some fresh fuel in the tank if its low see if that improves things.
otherwise favourite culprets include the FPR and AFS
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peanut
Active member
yes thats true but jason didn't say it was misfiring but stuttering which would suggest a fuel delivery issue . It could be electrical but that would tend to show itself on starting and idle and right through the acceleration and cruising speed range.
Its one of those problems that will probably need a comprehensive step by step test of everything to find the source of the problem.
peanut
Active member
Clarkes Garage Manual is a brilliant resource for trouble shooting guides
Engine Hesitates or Stumbles During Acceleration. Possible Causes Checks Procedure Dead spot in Air Flow Sensor / Air Flow Meter (AFM) potentiometer. Test AFM. ELECT-19 Vacuum Leak. With a large vacuum leak, the car may idle correctly. However, as soon as you open the throttle, the car may hesitate, stumble, or even cutoff. The best way to look for vacuum leaks is to connect a source of compressed air (approximately 10 psi will do it) to the intake manifold with the engine not running and listen for air leaks. N/A Spark Plugs Fouled. Remove spark plugs and check condition. ENG-18 Engine Misses. Possible Causes Checks Procedure Bad spark plug wires. Run the engine in a dark area and look for arcing from the spark plug wires to the engine. N/A Cracked distributor cap. Remove cap and check condition. N/A Faulty spark plug. Remove spark plugs individually and inspect for broken or excessively worn electrode or cracked insulator. Check the condition of the spark plugs by color. ENG-18 Vacuum leak. Check for vacuum leaks by pressuizing the intake manifold with compressed air. Listen for leaks. N/A Clogged fuel filter. Replace filter. FUEL-03 DME Computer A faulty DME computer can cause a variety of starting and running problems. Normally, problems with the DME computer are the result of bad solder joints which can frequently be repaired. There's really no way to test the DME unless you can swap it into another vehicle or unless you can borrow a known good DME to install for testing purposes. And, even a good used DME computer is a little pricey. So, I don't like to run out and replace the DME unless I've eliminated all other possible causes. If you suspect the DME computer is bad, as a minimum, I would open it up and inspect for bad solder joints (and repair them) before replacing the computer.
Engine Hesitates or Stumbles During Acceleration. Possible Causes Checks Procedure Dead spot in Air Flow Sensor / Air Flow Meter (AFM) potentiometer. Test AFM. ELECT-19 Vacuum Leak. With a large vacuum leak, the car may idle correctly. However, as soon as you open the throttle, the car may hesitate, stumble, or even cutoff. The best way to look for vacuum leaks is to connect a source of compressed air (approximately 10 psi will do it) to the intake manifold with the engine not running and listen for air leaks. N/A Spark Plugs Fouled. Remove spark plugs and check condition. ENG-18 Engine Misses. Possible Causes Checks Procedure Bad spark plug wires. Run the engine in a dark area and look for arcing from the spark plug wires to the engine. N/A Cracked distributor cap. Remove cap and check condition. N/A Faulty spark plug. Remove spark plugs individually and inspect for broken or excessively worn electrode or cracked insulator. Check the condition of the spark plugs by color. ENG-18 Vacuum leak. Check for vacuum leaks by pressuizing the intake manifold with compressed air. Listen for leaks. N/A Clogged fuel filter. Replace filter. FUEL-03 DME Computer A faulty DME computer can cause a variety of starting and running problems. Normally, problems with the DME computer are the result of bad solder joints which can frequently be repaired. There's really no way to test the DME unless you can swap it into another vehicle or unless you can borrow a known good DME to install for testing purposes. And, even a good used DME computer is a little pricey. So, I don't like to run out and replace the DME unless I've eliminated all other possible causes. If you suspect the DME computer is bad, as a minimum, I would open it up and inspect for bad solder joints (and repair them) before replacing the computer.
Thanks for all your help. I looked and checked the distributor cap, ok - checked the leads, ok and the plugs, all ok. The car then drove smoothly again. When I used the car an hour later it was back. I'm going to put some time aside to look closely at these items. Best wishes Jason
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