I test drove a manual PT the other day. When I drove around a roundabout, the engine started to shake . I downshifted and accelerated, which stopped the shaking. The same thing happened again in 5th gear ascending a hill.

Is this normal?

Might have been the full race cam in it.........

Seriously I would be asking questions first. Maybe something like a shot spark plug or a plug lead and it's missing and shaking the engine a bit.

Went through all this with our 04 and eventually tracked it down to plugs and leads. Renewed and hasn't missed a beat since.

not normal .. concure with chief had it with the leads etc .. plums & Roses is auto 2.4lt I had put in fancy leads & plugs .. the plugs were NOT suitable after a few thousand kms she was missing at idle shook every now & again (like U described)... so I went back to "cheapies" to compare and she settled BUT .. ALSO NOW Plums & roses has decided she doesn't like the COLD and is not happy on start up .. gradually getting worse .. took three tries then a warm up rough idle before we stared moving (yesterday) .. BUT she is due for a service 100,000 .. suppose it is like anything mechanical they needs TLC before things BREAK not after ... she is booked in after Black opals 10,000 kms service ... he is running like a dream no shakin at all auto & cruise control & radio MUCH better than 05 as well
ALSO
Recall conversation with OUR Black Betty owner Tony & Maryanne .. they had a similar problem words were "ran like *&^^ CRAP" & needed service .. due to change in work place in opposite direction .. usual Mopar option was not an option ... so they canvassed a local mechanic who has worked on race cars & FANCY cars admitted not much with PTs .. BUT local to their work seemed like he knew what he was talking about ??? gave it a shot . PT hasn't run as good in AGES !! also a lot less in $$$ they have 160,000 on the 2lt manual & will have timing belt etc done next ... wish I had asked what they had done ... I assume oil filters and perhaps plugs????
not sure if this helps U any ... !!!

Just thought I would post an update on this issue.

I just drove this PT again, and it has been transformed.

It now runs as smooth as silk, with no more shaking, and it has more grunt too.

The spark plugs were changed from Champion to NGK LZTR4A-11 gaped at .040, and the factory Chrysler leads were changed to NGK spark plug leads.

Ok reads like we will start there again with Plums & Roses too .... also getting bearings done as that is the NOISE I am hearing in front left hand wheel ... ON the list thankyou !

rdster wrote:
Just thought I would post an update on this issue.

I just drove this PT again, and it has been transformed.

It now runs as smooth as silk, with no more shaking, and it has more grunt too.

The spark plugs were changed from Champion to NGK LZTR4A-11 gaped at .040, and the factory Chrysler leads were changed to NGK spark plug leads.

Quite common. The stock plugs aren't bad, the stock leads are. Gapping at 0.040 is as recommended by a tech service bulletin.