it sounds like the tach in the cluster

Roy

Answered by ASEMaster6371 (expert)
24,973 answers provided

That would be the first thought, however I've read about three people on another Toyota forum that had the same problem and replaced the tach to no avail. It sounds like a wiring problem, but one of the other people had it happen and there was no maintenance or part replacements done prior to it happening. There appears to be a surge suppressing capacitor on the ignitor/coil assembly and I'm wondering if that capacitor were to go bad would it cause this type of problem.

Response from bko1
1 question asked

Check the grounding circuit at the intake manifolds.
Ensure ignition coil + and - wires are not interchanged.
Which engine do you have? Manual or AT transmission?
Same engine replaced?

Answered by KHLow2008 (expert)
40,332 answers provided

Yes the same V6 engine was installed, it was out of a '93 Lexus, it is an automatic transmission. The coil wires cannot be interchanged since they are a keyed plug. All the grounds on the engine were tight.

Response from bko1
1 question asked

At the check connector terminal # 19 (Black wire) atttach a tachometer and test if it works.

Answered by KHLow2008 (expert)
40,332 answers provided

Which check connector? the one under the hood and the diagnostic connector under the dash are not numbered.
The grounds were all good and tight.

Response from bko1
1 question asked

The one underhood. Sorry I could not find any identification diagrms to show you. If you check from rear of DLC, you should see a black wire.

Alternatively you can start from igniter. Terminal # 4, Black wire.

Answered by KHLow2008 (expert)
40,332 answers provided