QuestionI have an 87 Jeep Cherokee, 4.0 inline 6, automatic four wheel drive, the speedometer doesn't work and the jeep also bucks while driving, as well as stalling when coasting or coming to a stop. Are the bucking and speedometer issues connected? In any case, what can I do to test the speedometer? I have replaced the fuel filter, spark plugs, air filter and a couple of worn vacuum hoses. Anything else I can do regarding the bucking/stalling issue? Please help.
Thanks.
AnswerThe camshaft position sensor is located in the distributor. It's frequently referred to as a pick-up plate. Sometimes on older jeeps it's a safe bet to replace it when a tune-up is done. Additionally, the distributor cap and rotor need replacing as well.
If it's not that then a bit more work and money would go in to replace the crankshaft position sensor which is located on the driver's side rear of the engine, going in to the bell housing area. These fail from time to time but mostly give a no-start condition.
The oxygen sensor is a suspect too since it deals with air/fuel ratio mixture but on a full decel the computer doesn't really look at this sensor for anything.
I doubt the speedo being inop is related. The 80's and early 90's vehicles just didn't have too much tied in to the engine as far as vehicle speed is related.
Map sensor is something to keep in mind too. Either throttle body mounted with a small 90 degree elbow or they have a couple of lines (A pair I think) that leads to maybe the firewall and a small black box with a vacuum fitting and three wires on it.
Doug
