diff --git a/index.d.ts b/index.d.ts
index ea0948d..e603ac6 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -32,11 +32,9 @@ export interface TxManagerConfig {
   ESTIMATE_GAS?: boolean
   THROW_ON_REVERT?: boolean
   BLOCK_GAS_LIMIT?: number
-  PRIORITY_FEE_GWEI?: number
   BASE_FEE_RESERVE_PERCENTAGE?: number
   ENABLE_EIP1559?: boolean
   DEFAULT_PRIORITY_FEE?: number
-  PRIORITY_FEE_RESERVE_PERCENTAGE?: number
 }
 
 export interface TxManagerParams {
@@ -80,7 +78,7 @@ export type MessageEvents = {
 }
 type TEventEmitter = typeof EventEmitter
 
-declare interface TxManagerEventEmmiter extends TEventEmitter {
+declare interface TxManagerEventEmitter extends TEventEmitter {
   on<U extends TxManagerEvents>(event: U, listener: MessageEvents[U]): this
 
   on(event: 'confirmations', listener: MessageEvents['confirmations']): Promise<TransactionReceipt>
@@ -92,7 +90,7 @@ export class Transaction {
   manager: TxManager
   tx: TransactionData
   private _promise: typeof PromiEvent
-  private _emitter: TxManagerEventEmmiter
+  private _emitter: TxManagerEventEmitter
   executed: boolean
   retries: number
   currentTxHash: string
@@ -100,7 +98,7 @@ export class Transaction {
 
   constructor(tx: TransactionData, manager: TxManager)
 
-  send(): TxManagerEventEmmiter
+  send(): TxManagerEventEmitter
 
   replace(tx: TransactionData): Promise<void>
 
@@ -120,8 +118,6 @@ export class Transaction {
 
   private _hasError(message: string, errors: (string | RegExp)[]): boolean
 
-  private _getGasPrice(type: 'instant' | 'fast' | 'normal' | 'slow'): Promise<string>
-
   private _getLastNonce(): Promise<number>
 
   private _getGasParams(): Promise<GasParams>
diff --git a/src/Transaction.js b/src/Transaction.js
index d6b0881..a9434ae 100644
--- a/src/Transaction.js
+++ b/src/Transaction.js
@@ -72,21 +72,27 @@ class Transaction {
 
     if (!tx.gasLimit) {
       const estimatedGasLimit = await this._estimateGas(tx)
-      tx.gasLimit = min(
-        estimatedGasLimit.mul(Math.floor(this.manager.config.GAS_LIMIT_MULTIPLIER * 100)).div(100),
-        this.manager.config.BLOCK_GAS_LIMIT,
-      )
-    }
+      const gasLimit = estimatedGasLimit
+        .mul(Math.floor(this.manager.config.GAS_LIMIT_MULTIPLIER * 100))
+        .div(100)
 
+      tx.gasLimit = this.manager.config.BLOCK_GAS_LIMIT
+        ? min(gasLimit, this.manager.config.BLOCK_GAS_LIMIT)
+        : gasLimit
+    }
+    // TODO: check if the new tx params is valid
     tx.chainId = this.tx.chainId
     tx.nonce = this.tx.nonce // can be different from `this.manager._nonce`
 
     // start no less than current tx gas params
     if (this.tx.gasPrice) {
       tx.gasPrice = max(this.tx.gasPrice, tx.gasPrice || 0)
-    } else {
+    } else if (this.tx.maxFeePerGas) {
       tx.maxFeePerGas = max(this.tx.maxFeePerGas, tx.maxFeePerGas || 0)
       tx.maxPriorityFeePerGas = max(this.tx.maxPriorityFeePerGas, tx.maxPriorityFeePerGas || 0)
+    } else {
+      const gasParams = await this._getGasParams()
+      tx = { ...tx, ...gasParams }
     }
 
     this.tx = { ...tx }
@@ -418,9 +424,15 @@ class Transaction {
    */
   async _getGasParams() {
     const maxGasPrice = parseUnits(this.manager.config.MAX_GAS_PRICE.toString(), 'gwei')
-    const gasParams = await this.manager._gasPriceOracle.getTxGasParams()
-    if (gasParams.gasPrice) gasParams.gasPrice = min(gasParams.gasPrice, maxGasPrice)
-    else gasParams.maxFeePerGas = min(gasParams?.maxFeePerGas, maxGasPrice)
+    const gasParams = await this.manager._gasPriceOracle.getTxGasParams({
+      isLegacy: !this.manager.config.ENABLE_EIP1559,
+    })
+    if (gasParams.gasPrice) {
+      gasParams.gasPrice = min(gasParams.gasPrice, maxGasPrice)
+    } else {
+      gasParams.maxFeePerGas = min(gasParams?.maxFeePerGas, maxGasPrice)
+      gasParams.maxPriorityFeePerGas = min(gasParams?.maxPriorityFeePerGas, maxGasPrice)
+    }
     gasParams.type = gasParams?.maxFeePerGas ? 2 : 0
     return gasParams
   }
diff --git a/test/TxManager.test.js b/test/TxManager.test.js
index 5afe0b1..6ac7ee1 100644
--- a/test/TxManager.test.js
+++ b/test/TxManager.test.js
@@ -57,54 +57,68 @@ const getOptions = async () => {
   return { network, provider, options }
 }
 
-const createTx = async transaction => {
-  const tx = this.manager.createTx(transaction)
+const sendTx = async tx => {
   const receipt = await tx
     .send()
     .on('transactionHash', hash => console.log('hash', hash))
     .on('mined', receipt => console.log('Mined in block', receipt.blockNumber))
     .on('confirmations', confirmations => console.log('confirmations', confirmations))
   console.log('receipt', receipt)
+  return receipt
 }
 
 const transactionTests = () => {
   it('should work legacy tx', async () => {
-    await createTx(tx1)
+    const tx = this.manager.createTx(tx1)
+    const receipt = await sendTx(tx)
+    receipt.type.should.equal(0)
   })
 
   it('should work eip-1559 tx', async () => {
-    await createTx(tx5)
+    const tx = this.manager.createTx(tx5)
+    const receipt = await sendTx(tx)
+    receipt.type.should.equal(2)
   })
 
   it('should fetch gas params', async () => {
-    await createTx(tx4)
+    const tx = this.manager.createTx(tx4)
+    await sendTx(tx)
   })
 
   it('should bump gas params', async () => {
-    await createTx(tx2)
+    const tx = this.manager.createTx(tx2)
+    await sendTx(tx)
   })
 
   it('should cancel', async () => {
-    await createTx(tx2)
+    const tx = this.manager.createTx(tx3)
+    setTimeout(() => tx.cancel(), 1000)
+    await sendTx(tx)
   })
 
   it('should replace', async () => {
-    await createTx(tx2)
+    const tx = this.manager.createTx(tx3)
+    setTimeout(() => tx.replace(tx4), 1000)
+    const receipt = await sendTx(tx)
+    receipt.to.should.equal(tx4.to)
   })
 
   it('should increase nonce', async () => {
     const currentNonce = await this.manager._wallet.getTransactionCount('latest')
     this.manager._nonce = currentNonce - 1
-    await createTx(tx4)
+    const tx = this.manager.createTx(tx4)
+    await sendTx(tx)
   })
 
   it('should disable eip-1559 transactions', async () => {
     this.manager.config.ENABLE_EIP1559 = false
-    await createTx(tx3)
+    const tx = this.manager.createTx(tx3)
+    const receipt = await sendTx(tx)
+    receipt.type.should.equal(0)
     this.manager.config.ENABLE_EIP1559 = true
   })
 
-  it('should send multiple txs', async () => {
+  it.skip('should send multiple txs', async () => {
     const genTx = value => ({
       value,
       to: '0x0039F22efB07A647557C7C5d17854CFD6D489eF3',