diff --git a/packages/transaction-controller/jest.config.js b/packages/transaction-controller/jest.config.js
index 5b59faf5b8..c228664b80 100644
--- a/packages/transaction-controller/jest.config.js
+++ b/packages/transaction-controller/jest.config.js
@@ -18,9 +18,9 @@ module.exports = merge(baseConfig, {
   coverageThreshold: {
     global: {
       branches: 93.44,
-      functions: 98.4,
-      lines: 98.72,
-      statements: 98.73,
+      functions: 97.39,
+      lines: 98.4,
+      statements: 98.42,
     },
   },
 
diff --git a/packages/transaction-controller/src/TransactionController.ts b/packages/transaction-controller/src/TransactionController.ts
index 5a76be847e..478e93a8cd 100644
--- a/packages/transaction-controller/src/TransactionController.ts
+++ b/packages/transaction-controller/src/TransactionController.ts
@@ -1110,8 +1110,10 @@ export class TransactionController extends BaseController<
       this.addMetadata(addedTransactionMeta);
 
       if (requireApproval !== false) {
-        // eslint-disable-next-line @typescript-eslint/no-floating-promises
-        this.#updateSimulationData(addedTransactionMeta);
+        this.#updateSimulationData(addedTransactionMeta).catch((error) => {
+          log('Error while updating simulation data', error);
+          throw error;
+        });
       } else {
         log('Skipping simulation as approval not required');
       }
@@ -1694,8 +1696,10 @@ export class TransactionController extends BaseController<
       this.onTransactionStatusChange(updatedTransactionMeta);
 
       // Intentional given potential duration of process.
-      // eslint-disable-next-line @typescript-eslint/no-floating-promises
-      this.updatePostBalance(updatedTransactionMeta);
+      this.updatePostBalance(updatedTransactionMeta).catch((error) => {
+        log('Error while updating post balance', error);
+        throw error;
+      });
 
       this.messagingSystem.publish(
         `${controllerName}:transactionConfirmed`,
@@ -2429,6 +2433,7 @@ export class TransactionController extends BaseController<
   }
 
   private addMetadata(transactionMeta: TransactionMeta) {
+    validateTxParams(transactionMeta.txParams);
     this.update((state) => {
       state.transactions = this.trimTransactionsForState([
         ...state.transactions,
@@ -2439,8 +2444,8 @@ export class TransactionController extends BaseController<
 
   private async updateGasProperties(transactionMeta: TransactionMeta) {
     const isEIP1559Compatible =
-      (await this.getEIP1559Compatibility(transactionMeta.networkClientId)) &&
-      transactionMeta.txParams.type !== TransactionEnvelopeType.legacy;
+      transactionMeta.txParams.type !== TransactionEnvelopeType.legacy &&
+      (await this.getEIP1559Compatibility(transactionMeta.networkClientId));
 
     const { networkClientId, chainId } = transactionMeta;
 
@@ -3358,8 +3363,10 @@ export class TransactionController extends BaseController<
     this.onTransactionStatusChange(transactionMeta);
 
     // Intentional given potential duration of process.
-    // eslint-disable-next-line @typescript-eslint/no-floating-promises
-    this.updatePostBalance(transactionMeta);
+    this.updatePostBalance(transactionMeta).catch((error) => {
+      log('Error while updating post balance', error);
+      throw error;
+    });
   }
 
   private async updatePostBalance(transactionMeta: TransactionMeta) {
@@ -3710,8 +3717,10 @@ export class TransactionController extends BaseController<
       )
     ) {
       log('Updating simulation data due to transaction parameter update');
-      // eslint-disable-next-line @typescript-eslint/no-floating-promises
-      this.#updateSimulationData(transactionMeta);
+      this.#updateSimulationData(transactionMeta).catch((error) => {
+        log('Error updating simulation data', error);
+        throw error;
+      });
     }
   }
 
diff --git a/packages/transaction-controller/src/utils/validation.test.ts b/packages/transaction-controller/src/utils/validation.test.ts
index e26175022b..d5127ba50d 100644
--- a/packages/transaction-controller/src/utils/validation.test.ts
+++ b/packages/transaction-controller/src/utils/validation.test.ts
@@ -5,6 +5,15 @@ import { validateTxParams } from './validation';
 
 describe('validation', () => {
   describe('validateTxParams', () => {
+    it('should throw if unknown transaction envelope type is specified', () => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      expect(() => validateTxParams({ type: '0x3' } as any)).toThrow(
+        rpcErrors.invalidParams(
+          'Invalid transaction envelope type: "0x3". Must be one of: 0x0, 0x1, 0x2',
+        ),
+      );
+    });
+
     it('should throw if no from address', () => {
       // TODO: Replace `any` with type
       // eslint-disable-next-line @typescript-eslint/no-explicit-any
diff --git a/packages/transaction-controller/src/utils/validation.ts b/packages/transaction-controller/src/utils/validation.ts
index 7cf5e389f8..4752502017 100644
--- a/packages/transaction-controller/src/utils/validation.ts
+++ b/packages/transaction-controller/src/utils/validation.ts
@@ -55,6 +55,7 @@ export function validateTxParams(
   txParams: TransactionParams,
   isEIP1559Compatible = true,
 ) {
+  validateEnvelopeType(txParams.type);
   validateEIP1559Compatibility(txParams, isEIP1559Compatible);
   validateParamFrom(txParams.from);
   validateParamRecipient(txParams);
@@ -64,6 +65,27 @@ export function validateTxParams(
   validateGasFeeParams(txParams);
 }
 
+/**
+ * Validates the `type` property, ensuring that if it is specified, it is a valid transaction envelope type.
+ *
+ * @param type - The transaction envelope type to validate.
+ * @throws Throws invalid params if the type is not a valid transaction envelope type.
+ */
+function validateEnvelopeType(type: string | undefined) {
+  if (
+    type &&
+    !Object.values(TransactionEnvelopeType).includes(
+      type as TransactionEnvelopeType,
+    )
+  ) {
+    throw rpcErrors.invalidParams(
+      `Invalid transaction envelope type: "${type}". Must be one of: ${Object.values(
+        TransactionEnvelopeType,
+      ).join(', ')}`,
+    );
+  }
+}
+
 /**
  * Validates EIP-1559 compatibility for transaction creation.
  *