Mitsubishi Legnum 1997 running rough

duncb, Nov 1, 5:20pm
Not a good couple of weeks for my older cars. Problem 1) Mitsubishi Legnum 1997 2.5 litre EC5W. Starts first time but when accelerating from slow revs it stutters until it gets to 3000 rpm and that it goes fine. When it is warmed up it idles but stutter about every second. When checking engine fault codes it comes up with 13 (Intake air temp sensor fault.) 14 (Throttle position sensor (TPS) fault.) and another 1 long and 10 short flashes. The engine error light has only gone on twice with many short trips. Once it is swiched off the error light goes away. The back plugs were replaced about 4 months ago when I replaced the rear rocker cover gaskets and spark plug gasket . I changed the Throttle position sensor with a second hand one but this has made no difference. Distributor has no visible cracks and front plugs appear to be sparking fine. When this first started I had run low on fuel (No I did not run out of petrol) and when it first stuttered I thought maybe the fuel filter was the problem but this does not seem to be consistent with running better at higher revs. One thing is the item below the throttle body is making a noise. I don't even know what it does. Photo here.
Any suggestions.

intrade, Nov 1, 5:43pm
you want to open the computer soonest and look for leaking caps. mitsubishi was world first to have onhanglow crapacitors fitted. They all followed suit now its only garabage but be glad you only have 1 computer to fail most likely.

duncb, Nov 1, 6:31pm
I haven't even thought that the ECU might be at fault. Anyone else had a problem with one of this age?

curlcrown, Nov 2, 8:08am
The first thing to do would be replace they remaining 3 old spark plugs.

duncb, Nov 2, 8:35am
I forgot to mention that I did replace the front spark plugs last week.

intrade, Nov 2, 9:11am
why would you replace 1 spark plug ? Do you also just brush 1 tooth?

duncb, Oct 29, 2:59pm
I replaced plural spark plugs NOT 1. They have all been replaced this year. The reason the back ones were replaced first is because you have to take the intake manifold and all the connections off to get to the back spark plugs. Since I had to do that to replace the back rocker cover gasket I replaced the back sparks plugs as a matter of course rather than they were desperately in need of replacing

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