The enging is running very rough like timing missing at both idle and higher speeds. I had the same problem several months ago and when i changed the distributor cap/rotor and plugs and wires and the problem was solved. It seems like the same symptoms as before ,but would wires and cap get worn that soon, just seven months ago?At this time the wires look fine and cap/rotor has no unusual wear. I did change the plugs just a few days agoand it didn't seem to help much. When I accelerate, I hear the engine vibrate pretty bad like it is missing in tha timing and definate loss of hp, I can barely make it up hills anymore. Any suggestions, I would appreciate, thanx.

 

How many miles on the engine? I am only a shade tree (hobby) mechanic but I have three Sentra 200 sx a full car lift and tools and have done a lot of work on them. They are 95 and 96 models but I think the 1.6L engine is the same in your 94 model.

Other than computer / injector trouble I would think one possiblity might be the distributor has rotated some. Did you loosen the two 12MM bolts on each side of the distributor when you did the work last time and forgot to re-tighen them? If they are not loose then maybe the timing chain drive spocket has slipped. This is an interference engine meaning that the pistons will contact any open valves if the chain down right fails while the engine is running. I don't know how much the timing can get off before contact happens.
The lower sprocket is held true on the crankshaft with a key in a key-way. If that key has sheared that would cause this problem.
The bolt at the end of the crankshaft holds it all together and is really tight. If the key sheared that preasure from the bolt is all that would be keeping the spocket from slipping on the crankshaft. The bolt sandwhiches the harmonic balancer (fan belt pulley) a spacer and then the timing chain spocket. Everything except the pulley is contained inside the timing chain cover that covers the entire face of the engine block under the head and behind the waterpump and pulley.

This engine has two timing chains with tensioners on each. An upper chain and a lower chain linked by a double spocket. The tension is applied via nylon guides dirrectly against the chains. They wear down allowing the chains to become loose. I replace them in my 95 200sx last summer. I don't know how many miles were on it because I bought it on ebay with the odometer broken and showing 40K. After my daughter had been driving it for almost two years and the sprockets and tensioners where worn out but it still ran fine. Had a lot of chain slapping noise at the top of the engine at idle. I guess it has well over 200K on it. I have my 96 torn down now and it is needing tensioner guides but the sprockets and chains look fine. It has 166K on it but oil changes can make a big difference so mileage is not the only factor.

See the timing chain spocket here:

http://www.flickr.com/photos/9222512...7594347547443/


feel free to look around. I have several pictures of the three cars in various stages of repair.

http://www.flickr.com/photos/9222512...7594347547443/

 

Depending on the brand of plugs and wires you put in I have a family memeber that put new domestic wires in his import and burned them in 3 days imports will run 20000 volts hotter the domestic if you have the demestic try ngk