diff --git a/README-CN.md b/README-CN.md
index e200351..3f99472 100644
--- a/README-CN.md
+++ b/README-CN.md
@@ -206,9 +206,9 @@ POST /requests/{:id}/speedup
 
 #### 请求参数
 
-| 参数名       | 值    | 是否必须 | 说明                              |  
-|-----------|------|------|---------------------------------|  
-| fee_limit | 1FIL | 否    | 允许最大消耗的GAS费用,不传系统自动预估，值越大上链时间越快 |  
+| 参数名       | 值    | 是否必须 | 说明                    |  
+|-----------|------|------|-----------------------|  
+| fee_limit | 1FIL | 否    | 允许最大消耗的GAS费用,不传系统自动预估 |  
 
 #### 请求示例
  ```json
diff --git a/README.md b/README.md
index 7f2ffec..75522cd 100644
--- a/README.md
+++ b/README.md
@@ -205,9 +205,9 @@ POST /requests/{:id}/speedup
 > This does not guarantee the message will be on-chain. Check the request status again after a while and try multiple times if needed.
 
 #### Request parameters
-| Parameter | Value | Required | Description                                                                                                          |  
-|-----------|-------|----------|----------------------------------------------------------------------------------------------------------------------|  
-| fee_limit | 1FIL  | No       | Maximum allowable gas fee; if not provided, the system estimates; the higher the value, the faster the on-chain time |  
+| Parameter | Value | Required | Description                                                       |  
+|-----------|-------|----------|-------------------------------------------------------------------|  
+| fee_limit | 1FIL  | No       | Maximum allowable gas fee; if not provided, the system estimates; |  
 
 #### Request Example
  ```json
diff --git a/service.go b/service.go
index e94eeb0..6f1a1b0 100644
--- a/service.go
+++ b/service.go
@@ -864,14 +864,16 @@ func (s *Service) replaceMessage(ctx context.Context, id uint, mss *api.MessageS
 
 	defaultRBF := messagepool.ComputeRBF(msg.GasPremium, cfg.ReplaceByFeeRatio)
 
-	msg.GasLimit = 0 // clear gas limit
+	//msg.GasLimit = 0 // clear gas limit
+	msg.GasFeeCap = abi.NewTokenAmount(0)
+	msg.GasPremium = abi.NewTokenAmount(0)
 	ret, err := s.api.GasEstimateMessageGas(ctx, &msg, mss, types.EmptyTSK)
 	if err != nil {
 		return fmt.Errorf("failed to estimate gas values: %w", err)
 	}
 	msg.GasPremium = big.Max(ret.GasPremium, defaultRBF)
 	msg.GasFeeCap = big.Max(ret.GasFeeCap, msg.GasPremium)
-	msg.GasLimit = ret.GasLimit // set new gas limit
+	//msg.GasLimit = ret.GasLimit // set new gas limit
 
 	mff := func() (abi.TokenAmount, error) {
 		return abi.TokenAmount(config.DefaultDefaultMaxFee), nil