Mileage is 236,000 km (147,500 miles exactly) right now. The issue I experience when the motor is cold isn't a ticking problem...I know there's a fix for that by gradually revving up to 3,000 rpm over 15 seconds and dropping the throttle to let it idle for a further 15 seconds. I don't know how to describe it, other than the idle is extremely rough and putting it into gear makes it worse. That being said, I use Motorcraft Synthetic Blend 10W-30 motor oil, with an OEM Mitsubishi or sometimes ACDelco PF1127 oil filter. I'm a regular on BITOG, and Motorcraft has proven to be an excellent motor oil, which is why I use it (impressive UOA results). Temperature in my area ranges from 17 - 30 Celsius (63 - 86 Fahrenheit) at the moment.

Worthy of note, there is a lack of power under heavy acceleration. If I floor it, even if it down shifts, it accelerates extremely slowly. Also, I average 15.7 MPG at best (80% highway/20% city). Thanks again for all your input!

 

I still would suggest doing a compression test to eliminate any possible internal engine issues then go from there.

 

If this helps at all, here's a list of items I replaced as part of a huge maintenance I did this summer. Instead of selling it off, I decided I want to keep it, so hence the expenditure:
[ul][*]OE Timing belt[*]OE Water pump[*]OE Thermostat[*]Upper and lower radiator hoses (OEM)[*]OE Fan clutch[*]OE Brake booster pulled off the yard[*]OE PCV valve and valve cover gaskets[*]Re-cored radiator[*]OE shocks[*]OE Rotors and pads[*]OE Tie rod ends[*]ACDelco 41-802 platinum plugs[*]OE Distributor cap[*]OE Plug wires[*]Front drive axle solenoid valve[*]Oil pressure sensor[*]OE Engine mounts[*]OE Emissions solenoid[*]OE Steering wheel bearing[/ul]

 

Definitely going down that route, already made an arrangement on Wednesday. If not, I'll check to see cat. converter. Thank you!

 

if the test does not show anything,u might want to retune your engine.
u did mention replacing the distributor cap.maybe your timing is a little off.
i've experience it b4 on my LO47,the power loss is dramatic.a slight turn on the distributor makes lots of different.

what is your idling speed right now?

 

My idle speed is 900 rpm with the AC compressor engaged. Without the AC, it's round about 550 rpm IIRC - I'll have to check. That being said, the revs are stable and there is no fluctuation. Usually have a habit of cleaning out my throttle body, MAF and IAC every third oil change at most.

The mechanic who replaced my distributor rotor, wiresand cap attempted to turn the distributor slightly, but said it wouldn't be perfect and that I would need to take it to somebody with a "laser gun" to make sure its precise. Is such equipment necessary when adjusting engine timing?

Also, what's the best way to tell if my cat is faulty - just remove it and see how the truck runs? They are an expensive item, and I think I would end up ordering it off RockAuto if it absolutely needs replacing. $193 with shipping to Kuwait (for an aftermarket one) is a lot cheaper than paying the dealer upwards of $500 for OEM. [:-] Obviously you get what you pay for, but since we don't have emissions testing, I suppose it wouldn't matter so long as a catalytic converter is there.

Finally, would a faulty MAP sensor cause these symptoms? Where is the MAP sensor located on a12-valve 6G72? Thanks again!

 

there u go,
he turned the distributor without using the timing light.
only very2 experienced mech can do this.
the timing light is mandatory to turn the distributor.its the only way to make sure the spark is send at the precise moment eg 7 degree BTDC.
once u get this right the accel problem will be solved.

 

clogged cat would be noticable with a rotten egg smell, should trigger a check engine light as well, sounds like your missing a cylinder at idle, pull the plug wires while it is idling and see if one of them doesn't change the engine, if one doesn't then you know its the one not firing for whatever reason

 

Thanks again, it's definitely got to be the ignition timing that's causing the shuddering and acceleration problem. The compression test went well, there's nothing wrong with the engine. That being said, my vehicle does not come with oxygen sensors or a cat - so that takes those out.

I'm going to have to find a reputable shop to adjust the timing for me - dealer says the truck has to stay for 3-4 days. They said if I get a quick service (oil and filter change) done, they could get it done sooner...but I don't want any more of that 20W-50 engine oil when we're almost into winter.

 

3-4 days just for tuning.
that dealer must be joking.
its a quick job really.never takes longer than 15 minutes.