Truck Repair: Engine noise, ford explorer 4x4, crankshaft sensor

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Followup To
Question -
I know you only say diesels but no one else is available. It may be a simple thing you can answer. I have a 91 ford explorer 4x4 Automatic with a 94 engine. It is a 4 litre v6 pushrod engine. I have no anti knock sensors or camshaft sensors. I do have a crankshaft sensor. It ran great for 6 months with new motor. The noise was told was carbon build up in the combustion chamber. We sprayed some kleener in it. It is still there.When we take off spark plug#1 it goes away? Also have done the engine, oil treatments. the noise is like a clicking and not to loud but is getting worse. I was also told low octane knock or preignition. Is it lifters or rod bearings? If you cannot help could you refer me to someone who can?  This only happens under acceleration around 1200rpm.when warm. Thank you. Deb.
Answer -
I have to tell you that this is my Opinion, please only use it as a reference.  From what you said about it only doing it warmed up, and under acceleration; it could be either the lifter (have the rockers been adjusted?) or the rod bearing.  BUT with you removing the #1 spark plug wire and it stops......That would be a sign of a rod bearing because at that point you are removing the stress on the bearing due to there not being the "explosion" shoving the piston down.  Is the noise still there if you remove a plug wire from any other cylinder?  If so disreguard the rod bearing comment!  What do the spark plugs look like?  Do they show signs of running lean (white in color)? Are the carboned up?  What Octaine fuel are you running currently?  

The spark plugs are new platinum. The previous one on #1 did showed a very little white. I run regular unleaded gas. The rockers have not been touched yet. Although i forgot to mention we had it scanned and it came up with codes 85,87. OBD1 I think 85 means it is a little lean. Sometimes i get the smell of gas in the cab when starting. We tested the valve to the carbon canister and the white wire we had to ground. It used to start hard when cold but now it seems to start good. It idles good. The noise is not on any other spark plugs.
Should i keep driving the truck? will i do further bad damage? I have to wait to afford to take it in the shop.   Thanks.  

Answer
I'm not sure if you should drive it or not with out hearing it for myself.  If it sounded like a rod bearing to me....then I would say do not drive it because if it is "going" bad then you can get off pretty cheap on parts, further damage may require a new crank and rod {I HIGHLY doubt that it was is going on though!}  

I would like to suggest doing a compression test on the engine (the tools are cheap for this).  If you get more than a 10% difference between cylinders then there is problyms.  I am interested if #1 will be a lower compression.  Some of the smaller Ford engines had problyms with burning valves.  Let me know if you need info on how to do a compression test.