gu 98 tb4.5 rough idle

[vzmaniac]

hi all

bought my duel fuel patrol a few weeks ago and on gas it has been idling ever so slightly rough on startup and sitting on 1000rpm for a few minutes then it calms down and comes back down to 700rpm.. at first i thought it was the gas system (been doing a fun problem solving with the gas first the radiator hoses to it were stuffed along with rusty clamps... then i found the flashlube system hoses were all split... yay)

anyway long story short put half a tank of 98 octane in (tank was already half full) and have run it on petrol for a tank to clean out whatever petrol was in it from previous owner... and its doing the same thing on petrol. but its also playing up sitting at lights etc on petrol (doesnt do it on gas)

just wondering if there is anything i could look at that could be causing the issues

[lhurley]

When you first start the car and the revs go up then settle down, thats to warm the car up ever so slightly so that when you take off its not stone cold. Also gas accentuates any engine "issues" such as rough idle, tappets etc.

Does it still idle rough when you give it a bit of throttle?? ie instead of idling at 700, get it up to about 750??

Im only saying that as its an old car and you need to bump up the idle after a while. Also when was the last service? what did they do? what up keep has been done recently.

There are a few different reasons as to why its rough, but thats a start.

[vzmaniac]

[QUOTE=lhurley;292193]When you first start the car and the revs go up then settle down, thats to warm the car up ever so slightly so that when you take off its not stone cold.[\quote]

this pretty much completely explains whats going on thanks for that.

i now think on petrol may have just been whatever crap the previous owner had put into it (probably e10 knowing my luck :P) might drain the rest of the petrol and put a full tank of 98 and a fuel filter change.

thanks for the reply :D

[lhurley]

No problem mate, glad to help. I occasionally run some of that injector cleaner through mine, seems to make it a little nicer.

Im with you on the e10, i hate the stuff.