I have a SOnata GLS 2.0 AUTO, 4 cyl yr 2003 with 84000km.

I have recently come across a weird issue with the engine. The Symptons are as such :


On start - everything is fine
After travelling a short while - engine looses power

multiple symptons :
1. Increase Rev fast to 4000 - 4500RPM RPM whilst cruising at 2000RPM
> gear drops, but there is little driving power

2. Step on paddle at 1000RPM> Engine struggles to reach 2000RPM. Step on paddle further, Engine flutters and RPM Drops to approx 1500.


No ENgine Check Lights
Sent to Hyundai Service and hookep up with Diag Computer - No Error code

The above happens intermittently

When the above occurs, i would switch off the engine and turn back on after 10 secs, and everything returns to normal for a short while till it acts up again.

Notice this has just started after I removed my fuel tank and repaired a crack on the tank. Checked all connections to Fuel pump and everything is ok. All hoses fitted in properly. No more fuel leaks.


Please advise.

jUST TO ADD ON.

I changed my crankshaft pulley at the same time as the fuel tank service.

I read another post regarding crank shaft pulley sensor issues reporting similar "NO POWER" Symptoms

Could someone help advise further..

What could have gone wrong and what should be done?


Thanks

1) did you damage the CPS when you changed the crankshaft pulley? other posibilities are MAF sensor and TPS (throttle position sensor)....a faulty MAF sensor will not always trigger the CEL but the other two sensors should do

I doubt that the sensor is spoilt as the Hyundai Service Conputer hookup did not pick up any spoilt sensors.

Could you advise

1. Could wrong installation of the crankshaft pulley cause the problem

2. how do i allign the sensor and the pulley? Are there any marks?

3, any other way to troubleshoot if the CSP sensor is the cause of the problem or could it be the MAF?


Thanks
ralph

Dear shades,

I am addressing your initial problem.

All of the symptoms you are reporting, engine losing power, 4000 rpm surge, 1000-2000 rpm fluttering indicate:

Bad Throttle Position Sensor. This may be failing but not completely failed, so you are getting no diagnostic trouble code. This can be tested before replacement to confirm my diagnosis, but mine is from hard experience.

Byron