[3rd Gen : 96-00]: Power Loss - Spark Plugs?
#1
06-22-2019, 04:06 PM
Power Loss - Spark Plugs?
So a 1999 base Voyager (Plymouth re-badge of Caravan) with a stock 2.4 liter 4-cylinder and a three-speed slushbox is never going to win any drag races...unless, perhaps, against a battery-powered Genie lift! But, lately...and very occasionally... the power train has been getting extremely weak. As in, foot to the floor and kicking down into first gear to maintain 40 mph on the freeway. Then, a few seconds later, power comes back for a while. It seems almost as if a cylinder or two is cutting out and back in, but there's no unusual vibration or other signs of distress other than the occasional loss of power.
Since the van has unknown but very high mileage (odometer reads 154K, but car data report showed 274K as of previous state inspection...go figure), I thought it might be a good idea to replace the spark plugs. I just finished the job; first time I've changed spark plugs myself since the 2.2 liter on my old Plymouth Horizon in the late '90s. That was a walk in the park by comparison (the 2.2 was specifically designed to facilitate owner maintenance); this was a bear. The tower wells are deep enough to require a long extension, but there's not enough clearance between them and the wiper assembly to get the extension and socket in and out. I eventually devised the plan of dropping in the socket, and then inserting the long extension down the hole, and finally connecting the ratchet to it. To extract the spark plug I first had to pull the extension from the socket (letting the socket drop back down the well), then reach into the well with my shorty extension plus a universal joint to latch on to the socket and retrieve it and the plug. I used new Champion RC12PYP-7071 platinum plugs, gapped to .050 as per the service manual, and I used antiseize on all of the plug bases and dielectric grease on all of the electrode connections.
The good news is that the old plugs looked good! No oil fouling, no carbon, nothing other than a little bit of light gray deposits. And all were within .010 of the correct gap setting. If they hadn't been platinum plugs of uncertain history from a very high mileage engine I would have seriously considered cleaning, re-gapping, and reinstalling them and then returning the new plugs to the store. The bad news is...the old plugs looked good! It's unlikely, in my estimation, that they were the cause of my infrequent but bothersome power losses. Would anyone have suggestions as to what I should investigate next if the problem recurs?
Since the van has unknown but very high mileage (odometer reads 154K, but car data report showed 274K as of previous state inspection...go figure), I thought it might be a good idea to replace the spark plugs. I just finished the job; first time I've changed spark plugs myself since the 2.2 liter on my old Plymouth Horizon in the late '90s. That was a walk in the park by comparison (the 2.2 was specifically designed to facilitate owner maintenance); this was a bear. The tower wells are deep enough to require a long extension, but there's not enough clearance between them and the wiper assembly to get the extension and socket in and out. I eventually devised the plan of dropping in the socket, and then inserting the long extension down the hole, and finally connecting the ratchet to it. To extract the spark plug I first had to pull the extension from the socket (letting the socket drop back down the well), then reach into the well with my shorty extension plus a universal joint to latch on to the socket and retrieve it and the plug. I used new Champion RC12PYP-7071 platinum plugs, gapped to .050 as per the service manual, and I used antiseize on all of the plug bases and dielectric grease on all of the electrode connections.
The good news is that the old plugs looked good! No oil fouling, no carbon, nothing other than a little bit of light gray deposits. And all were within .010 of the correct gap setting. If they hadn't been platinum plugs of uncertain history from a very high mileage engine I would have seriously considered cleaning, re-gapping, and reinstalling them and then returning the new plugs to the store. The bad news is...the old plugs looked good! It's unlikely, in my estimation, that they were the cause of my infrequent but bothersome power losses. Would anyone have suggestions as to what I should investigate next if the problem recurs?
