No Power/dropping Tach (sc400/95)

[stau]

SC400, 95, 125K--Driving home and at a stop light I noticed a change in engine dynamics. Engine developed a muffeled sound and as best I could describe it –almost like it was the potato in the tail pipe. Now, when I took off from the light, I had little power. Also as I increased the power while in 1st the tach “bounced around” and dropped to zero but the car keep plodding along (thus it didn’t reflect the decrease in RPMs), shifted into second tach came back to est RPM, then dropped again to zero as I asked for more power (very slowly at that) and shifted again but remained at the designed RPMs. Funny smell from exhaust, no check engine light, Xmission fluid is normal flavor. Sometimes I have been concerned about the Xmission as it makes a “whinning” noise when it first starts out but then clears up and no slippage. No real visible signs under car or engine comparment.

Now before I throw up my hands and take it to the shop—what are some quick checks???

Thanks to the forum and the tech info on timing belts, window regulators, and front end bushings as I am getting ready to do the timing belt/pump (maybe).

[stau]

SC400, 95, 125K--Driving home and at a stop light I noticed a change in engine dynamics. Engine developed a muffeled sound and as best I could describe it –almost like it was the potato in the tail pipe. Now, when I took off from the light, I had little power. Also as I increased the power while in 1st the tach “bounced around” and dropped to zero but the car keep plodding along (thus it didn’t reflect the decrease in RPMs), shifted into second tach came back to est RPM, then dropped again to zero as I asked for more power (very slowly at that) and shifted again but remained at the designed RPMs. Funny smell from exhaust, no check engine light, Xmission fluid is normal flavor. Sometimes I have been concerned about the Xmission as it makes a “whinning” noise when it first starts out but then clears up and no slippage. No real visible signs under car or engine comparment.

Now before I throw up my hands and take it to the shop—what are some quick checks???

Thanks to the forum and the tech info on timing belts, window regulators, and front end bushings as I am getting ready to do the timing belt/pump (maybe).

and will start well but while in park, you increase RPMs the tach drops to zero but again, the engine increases --as the engine decrease back to around 750 rpms, tach comes back.

[jzz30]

sounds like a bad coil.

[powerjunkie]

SC400, 95, 125K--Driving home and at a stop light I noticed a change in engine dynamics. Engine developed a muffeled sound and as best I could describe it –almost like it was the potato in the tail pipe. Now, when I took off from the light, I had little power. Also as I increased the power while in 1st the tach “bounced around” and dropped to zero but the car keep plodding along (thus it didn’t reflect the decrease in RPMs), shifted into second tach came back to est RPM, then dropped again to zero as I asked for more power (very slowly at that) and shifted again but remained at the designed RPMs. Funny smell from exhaust, no check engine light, Xmission fluid is normal flavor. Sometimes I have been concerned about the Xmission as it makes a “whinning” noise when it first starts out but then clears up and no slippage. No real visible signs under car or engine comparment.

Now before I throw up my hands and take it to the shop—what are some quick checks???

Thanks to the forum and the tech info on timing belts, window regulators, and front end bushings as I am getting ready to do the timing belt/pump (maybe).

and will start well but while in park, you increase RPMs the tach drops to zero but again, the engine increases --as the engine decrease back to around 750 rpms, tach comes back.

actually sounds like a bad catilatic converter, sometimes the catalist breaks up and pluggs the exhaust system up...hence the smell

quick check is to unbolt (or loosen) the exhaust at the manifolds....fire it up if it revs fine (but loud) and seems to run good ...then your exhaust is plugged. great time to add a set of high flow converters.

hope this helps....if ya find the cause..post it up.

[stau]

Was the driver's side coil--thanks for the info and late reply.