I've been having this problem off and on for the past year. Nothing I've tried has solved it. It's hard to troubleshoot because it will show up for a week or so then disappear for awhile. This last time it ran good for almost 2 months before it started acting up again.
Here are the basic symptoms:
1) Hard starting - Will crank forever unless I do the 'flooded start' procedure and hold the accelerator peddle to the floor while cranking. Once it starts it runs incredibly rough. And the RPMs hold at about 1100.
2) Throttle response is non-existent. Any application of throttle will bog it out and cause it to hesitate badly.
3) After a few minutes of this the engine will smooth out and the RPMs will drop to normal idle. It's not a gradual smoothing out either. It's near instantaneous. Almost like a switch is being thrown.
4) Occasionally after running for awhile the engine RPMs will creep up at idle. It will run about as high as 1500-1700 RPM. This is intermittent and they will eventually fall again.
If it starts normally none of the other symptoms will show themselves. I can also tell when it is going to start normally versus acting up. When I first turn the key to run the fuel pump primes. When it is going to start normally the fuel pump only primes for about 1 second. If it's going to act up the fuel pump runs for about 4-5 seconds.
The following parts/sensors have been replaced either trying to track this issue down or for other reasons with the issue occuring pre and post replacement:
TPS
MAP
CTS
Injectors
Fuel Pump
Plugs & Wires
At no point has a code ever been thrown.
This is on a 92 XJ 6cyl with the AW4.
Ideas? I'm stumped. I've never taken this pig into a shop and I don't plan on it now but I'm out of ideas.
Here are the basic symptoms:
1) Hard starting - Will crank forever unless I do the 'flooded start' procedure and hold the accelerator peddle to the floor while cranking. Once it starts it runs incredibly rough. And the RPMs hold at about 1100.
2) Throttle response is non-existent. Any application of throttle will bog it out and cause it to hesitate badly.
3) After a few minutes of this the engine will smooth out and the RPMs will drop to normal idle. It's not a gradual smoothing out either. It's near instantaneous. Almost like a switch is being thrown.
4) Occasionally after running for awhile the engine RPMs will creep up at idle. It will run about as high as 1500-1700 RPM. This is intermittent and they will eventually fall again.
If it starts normally none of the other symptoms will show themselves. I can also tell when it is going to start normally versus acting up. When I first turn the key to run the fuel pump primes. When it is going to start normally the fuel pump only primes for about 1 second. If it's going to act up the fuel pump runs for about 4-5 seconds.
The following parts/sensors have been replaced either trying to track this issue down or for other reasons with the issue occuring pre and post replacement:
TPS
MAP
CTS
Injectors
Fuel Pump
Plugs & Wires
At no point has a code ever been thrown.
This is on a 92 XJ 6cyl with the AW4.
Ideas? I'm stumped. I've never taken this pig into a shop and I don't plan on it now but I'm out of ideas.
