TL Misfire Code 1399

I recently had my timing belt replaced on my '99 TL and now I have been getting code 1399 every few days...shop has given me a couple of different answers...bad gas (same gas I have used for two years) then faulty coil...after changing to a different fuel supplier.

My question is can a faulty timing belt or improper install cause this code (it seems odd that the code would start a day after the belt replacement).

Thanks in advance

B

Let me save you 500.00
Your egr ports are plugged. my car was listing code 1399.
The dealer SAID they took off the whole intake manifold to clean out the carbs. HOw ever i think they only did a throttle body flush!