azstang86

I need help tracking this problem on my car. Engine size is 3.9 and the "check engine" light is not on. When accelerating uphill my car tends to jerk.

I have made these changes so far.

Changed transmission
new spark plugs
new fuel filter
new air filter

what else do you thing is the problem?

PNYXPRESS

wrong gear, too low of rpms?

azstang86

where to start?

PNYXPRESS

What gear are you in going up these hills? Try downshifting to bring up the rpms until it doesnt buck. should be no less than 1200 rpms.

BlindGUYnAR

Normally misfire maybe, but that should set CEL so who knows is it auto or manual trans?

v6power88

Clogged cat

azstang86

Its a automatic v6 3.9 I am going to change out the coils, coil ignition, spark plug wires, and spark plugs. Clean the MAF sensor and change the O2 sensor.

corker

Before you throw more money at this problem, invest in a scanner and take a look at live data while the problem is happening. Post result here and we can help you pinpoint the problem. Tough to troubleshoot a problem without having any direction. This could be as simple as a glitchy cam sensor that doesn't set a code.
Corky

azstang86

What time of scanner do you recommend? Please leave the link for me thanks

corker

Sorry, I can't help here. I use my buddy's Snap On scanner when I have problems (ridiculously expensive). There have been so many changes recently to scanner apps. There are blue tooth ones that sync with an app on your smart phone. Perhaps, one of the experts on this site can help here. The important functionality you need is to be able to see O2 sensor data and fuel trims - live. This will certainly help pinpoint your problem.
Corky