My '95 (2.7L) has several problems or one big inter-related problem that may finally be shaking out after a year of looking for the reason. I'd never heard of a forum for help with my truck before so I'm hoping you all have some insights. I do my own basic maintenance but I've got no manual so its a lot of question asking and research to yield successful major problem wrenching. The engine is eating the spark plug in cylinder 1 every 3-5 months; its been leaking coolant for a while but not from any obvious place and randomly the "check engine" light would come on, stay for a drive or four and then go off (this has happened about 6 times over the last year). No error codes were detected by the reader from the light being on.
Addressing the issues: first the check engine sensor and spark plug - I have replaced the spark plug 3 times over the last year. The truck runs rough when it starts and then smooths out after about 5 minutes and runs fine for the rest of the day with a small miss from time to time. The truck runs in this manner until there is a sudden lunging of the engine, the check engine light goes on and there is no power. I check the gap on the #1 spark plug and it has become so large it can no longer work. A new spark plug makes it all run fine for several months (with the possible slight miss still felt). I've checked timing, spark plug wires and finally had a mechanic look at the problem with no success. Finally last week the check engine light came on again but it said the first bank O2 sensor had failed. I changed it and figured that would account for the eating of the spark plug. And hoped all would be fine. But no.
Unfortunately when I was changing out the sensor (at 1 am) I noticed coolant dripping out of the joint btwn the manifold and the exhaust pipe (before the cat). Maybe this explains why when searching for the leak and finding a small pin prick in a hose, changing the hose did not fix the leak. I need to put water/coolant into the radiator once every 8 days or after long trips.
When I replaced the sensor I also checked the spark plug and the gap was again huge. So I've put in a new spark plug. But this time the missing is very noticeable and I'm not all that comfortable driving it any where.
I want to figure out what is going on. Is the undetected leaking and the spark plug destruction related? Maybe a new head gasket? Is there a way to determine if the coolant is leaking into the #1 cylinder? Is it fixable? Is the problem something else all together? Does anybody have any ideas or insights? Questions?
There are about 247K miles on the truck now.