diff --git a/crates/flashblocks-rpc/src/rpc.rs b/crates/flashblocks-rpc/src/rpc.rs
index 093a1a6e..1e33fd4f 100644
--- a/crates/flashblocks-rpc/src/rpc.rs
+++ b/crates/flashblocks-rpc/src/rpc.rs
@@ -12,10 +12,11 @@ use jsonrpsee::{
     core::{async_trait, RpcResult},
     proc_macros::rpc,
 };
+use jsonrpsee_types::error::INVALID_PARAMS_CODE;
+use jsonrpsee_types::ErrorObjectOwned;
 use op_alloy_network::Optimism;
 use op_alloy_rpc_types::OpTransactionRequest;
 use reth::providers::CanonStateSubscriptions;
-use reth::rpc::server_types::eth::EthApiError::TransactionConfirmationTimeout;
 use reth_rpc_eth_api::helpers::EthState;
 use reth_rpc_eth_api::helpers::EthTransactions;
 use reth_rpc_eth_api::helpers::{EthBlocks, EthCall};
@@ -28,6 +29,15 @@ use tokio_stream::wrappers::BroadcastStream;
 use tokio_stream::StreamExt;
 use tracing::{debug, trace, warn};
 
+/// Max configured timeout for `eth_sendRawTransactionSync` in milliseconds.
+pub const MAX_TIMEOUT_SEND_RAW_TX_SYNC_MS: u64 = 6_000;
+
+/// Error code for timeout error.
+///
+/// Specs <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-7966.md#method-name>.
+// todo: replace with <https://github.com/paradigmxyz/reth/issues/18251>
+pub const ETH_ERROR_CODE_TIMEOUT: i32 = 4;
+
 /// Core API for accessing flashblock state and data.
 pub trait FlashblocksAPI {
     /// Retrieves the current block. If `full` is true, includes full transaction details.
@@ -88,6 +98,7 @@ pub trait EthApiOverride {
     async fn send_raw_transaction_sync(
         &self,
         transaction: alloy_primitives::Bytes,
+        timeout_ms: Option<u64>,
     ) -> RpcResult<RpcReceipt<Optimism>>;
 
     #[method(name = "call")]
@@ -236,9 +247,22 @@ where
     async fn send_raw_transaction_sync(
         &self,
         transaction: alloy_primitives::Bytes,
+        timeout_ms: Option<u64>,
     ) -> RpcResult<RpcReceipt<Optimism>> {
         debug!(message = "rpc::send_raw_transaction_sync");
 
+        let timeout_ms = match timeout_ms {
+            Some(ms) if ms > MAX_TIMEOUT_SEND_RAW_TX_SYNC_MS => {
+                return Err(ErrorObjectOwned::owned(
+                    INVALID_PARAMS_CODE,
+                    format!("time out too long, timeout: {ms} ms, max: {MAX_TIMEOUT_SEND_RAW_TX_SYNC_MS} ms"),
+                    None::<()>,
+                ))
+            },
+            Some(ms) => ms,
+            _ => MAX_TIMEOUT_SEND_RAW_TX_SYNC_MS,
+        };
+
         let tx_hash = match EthTransactions::send_raw_transaction(&self.eth_api, transaction).await
         {
             Ok(hash) => hash,
@@ -247,10 +271,11 @@ where
 
         debug!(
             message = "rpc::send_raw_transaction_sync::sent_transaction",
-            tx_hash = %tx_hash
+            tx_hash = %tx_hash,
+            timeout_ms = timeout_ms,
         );
 
-        const TIMEOUT_DURATION: Duration = Duration::from_secs(6);
+        let timeout = Duration::from_millis(timeout_ms);
         loop {
             tokio::select! {
                 receipt = self.wait_for_flashblocks_receipt(tx_hash) => {
@@ -267,11 +292,12 @@ where
                             continue
                         }
                     }
-                _ = time::sleep(TIMEOUT_DURATION) => {
-                    return Err(TransactionConfirmationTimeout {
-                        hash: tx_hash,
-                        duration: TIMEOUT_DURATION,
-                    }.into_rpc_err());
+                _ = time::sleep(timeout) => {
+                    return Err(ErrorObjectOwned::owned(
+                        ETH_ERROR_CODE_TIMEOUT,
+                        format!("transaction confirmation timed out after {timeout_ms} ms"),
+                        None::<()>,
+                    ));
                 }
             }
         }
diff --git a/crates/flashblocks-rpc/src/tests/rpc.rs b/crates/flashblocks-rpc/src/tests/rpc.rs
index a53fc374..2ce0118b 100644
--- a/crates/flashblocks-rpc/src/tests/rpc.rs
+++ b/crates/flashblocks-rpc/src/tests/rpc.rs
@@ -1,5 +1,6 @@
 #[cfg(test)]
 mod tests {
+    use crate::rpc::ETH_ERROR_CODE_TIMEOUT;
     use crate::rpc::{EthApiExt, EthApiOverrideServer};
     use crate::state::FlashblocksState;
     use crate::subscription::{Flashblock, FlashblocksReceiver, Metadata};
@@ -72,12 +73,13 @@ mod tests {
         pub async fn send_raw_transaction_sync(
             &self,
             tx: Bytes,
+            timeout_ms: Option<u64>,
         ) -> eyre::Result<RpcReceipt<Optimism>> {
             let url = format!("http://{}", self.http_api_addr);
             let client = RpcClient::new_http(url.parse()?);
 
             let receipt = client
-                .request::<_, RpcReceipt<Optimism>>("eth_sendRawTransactionSync", (tx,))
+                .request::<_, RpcReceipt<Optimism>>("eth_sendRawTransactionSync", (tx, timeout_ms))
                 .await?;
 
             Ok(receipt)
@@ -526,11 +528,13 @@ mod tests {
         node.send_payload(create_first_payload()).await?;
 
         // run the Tx sync and, in parallel, deliver the payload that contains the Tx
-        let (receipt_result, payload_result) =
-            tokio::join!(node.send_raw_transaction_sync(TRANSFER_ETH_TX), async {
+        let (receipt_result, payload_result) = tokio::join!(
+            node.send_raw_transaction_sync(TRANSFER_ETH_TX, None),
+            async {
                 tokio::time::sleep(std::time::Duration::from_millis(100)).await;
                 node.send_payload(create_second_payload()).await
-            });
+            }
+        );
 
         payload_result?;
         let receipt = receipt_result?;
@@ -538,4 +542,21 @@ mod tests {
         assert_eq!(receipt.transaction_hash(), TRANSFER_ETH_HASH);
         Ok(())
     }
+
+    #[tokio::test]
+    async fn test_send_raw_transaction_sync_timeout() {
+        reth_tracing::init_test_tracing();
+        let node = setup_node().await.unwrap();
+
+        // fail request immediately by passing timeout of 0 ms
+        let receipt_result = node
+            .send_raw_transaction_sync(TRANSFER_ETH_TX, Some(0))
+            .await;
+
+        assert!(receipt_result
+            .err()
+            .unwrap()
+            .to_string()
+            .contains(&ETH_ERROR_CODE_TIMEOUT.to_string()));
+    }
 }