Is this an engine knock?
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Joined: Feb 2010
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Is this an engine knock?
I have a 2002 Grand Caravan with 186,000 miles.
About 6 months ago it started making a violent clicking when I would drive up hills or try to accelerate. I thought it was the transmission because it would almost always go away when I dropped the transmission into 3rd gear. It was most prevalent at about 40 mph, rarely occurring below or above that.
About 2 months ago the engine started to run very roughly in idle. Once it was moving it was OK but not good in idle. When I put a full electrical load on it (lights, radio, both blower motors) it would idle even worse.
I was not getting any codes so I figured I would ignore it until it got really bad. Yesterday, in the rain, it got really bad and threw an engine code at me: P0302, misfire on cylinder 2. Here are the details:
P0302
Fuel Sys1 CL
Fuel Sys2 NA
Calc Load(%) 12.9
ECT(°F) 108
STFT B1(%) 1.6
LTFT B1(%) 0.8
MAP(inHg) 9.7
Eng RPM 1024
Speed(mph) 25
The front blower motor and resistor were both shot and I replaced them about a month ago. That seemed to reduce the problem, I think they were drawing a big electrical load. But now the problem is back
This all seems electrical to me, am I on the right track? Is it likely to be something stupid like plugs and wires? And am I hearing a knock as a result? It seems like all the other engine parameters are within norms.
About 6 months ago it started making a violent clicking when I would drive up hills or try to accelerate. I thought it was the transmission because it would almost always go away when I dropped the transmission into 3rd gear. It was most prevalent at about 40 mph, rarely occurring below or above that.
About 2 months ago the engine started to run very roughly in idle. Once it was moving it was OK but not good in idle. When I put a full electrical load on it (lights, radio, both blower motors) it would idle even worse.
I was not getting any codes so I figured I would ignore it until it got really bad. Yesterday, in the rain, it got really bad and threw an engine code at me: P0302, misfire on cylinder 2. Here are the details:
P0302
Fuel Sys1 CL
Fuel Sys2 NA
Calc Load(%) 12.9
ECT(°F) 108
STFT B1(%) 1.6
LTFT B1(%) 0.8
MAP(inHg) 9.7
Eng RPM 1024
Speed(mph) 25
The front blower motor and resistor were both shot and I replaced them about a month ago. That seemed to reduce the problem, I think they were drawing a big electrical load. But now the problem is back
This all seems electrical to me, am I on the right track? Is it likely to be something stupid like plugs and wires? And am I hearing a knock as a result? It seems like all the other engine parameters are within norms.
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Joined: Nov 2011
Posts: 197
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You are dealing with two separate issues. Electrical loads through the alternator would not cause the noise problem, they would only amplify an existing problem. Concentrate on the missfire issue with a compression test and fuel injector test to start with. Check your coils for output and change your spark plugs and wires.