miss

thedanned · Feb 20th, 2005, 09:11 PM

hello all, im new here, so if im posting in the wrong section please forgive. i recently received a free 1991 niss truck, 3.0 auto. it has a miss at idle and stumble on low rpm accel. its got spark at all, all injectors are firing. it does have a massive exhaust leak at the (dont know how cyls are #d on these things) pass side rear port. the rear stud has broken off and i was told this is a common occurance on these motors. its been leaking for several years now (my mom bought this new and racked up 309,000 action packed miles) and im pretty scared that it has burnt a valve due to the massive leak for so long. does anybody know of anything common that would cause a miss? does the map fail? does it have a map? i dont have much exp with nissans. any help would be greatly appreciated as this truck is in astonishingly good cond and i see no reason not to drive it, and i really dont want to have to do valves. thaks.

nova73guy · Feb 21st, 2005, 09:14 PM

First off, welcome to the forum! Hope you enjoy your membership.

I'm not real familiar with the trucks, especially that old. A misfire can be caused by several things: timing, spark plugs, gas, timing belt that has slipped, etc. With that many miles on the engine, I'd put my money on compression as the cause, especially if it's been driven hard that long. Best thing to do is search the forums. I know you'll probably hear that a lot, but I've found it's usually the quickest way to find the solution to my problems. Happy motoring!

**88pathoffroad** · Feb 22nd, 2005, 01:04 AM

An engine that old probably has so much build-up inside the intake and other areas that it needs a thorough going-over and cleaning of everything you can get to. Trouble-shoot one thing at a time, then fix it, move on to the next. Sounds like the exhaust leak should be first if you intend to keep the truck.

thedanned · Feb 22nd, 2005, 02:21 PM

yeah i fixed the exh yesterday and the miss lessened. i think it had someting to do with absolutely no backpressure on that hole. its still there, so now ill start goin thru everyting i did the other day, maybe i mised something or something.