Ryan-MI
NAXJA Forum User
- Location
- Grand Rapids, MI
I have a '99 XJ that makes a knocking noise only when I accelerate. When I let off the gas and just let it roll it's fine but once I accelerate it knocks. When I put it in park and step on the gas the engine sounds normal, no knocking of any kind.
I can't imagine it's a rod or valve knock because I had a remanufactured engine (all new internals) professionally installed about 8 months ago. The only aftermarket product I have on the engine is a cold air intake and a stainless steel header that had already cracked but was rewelded and re-installed along with a flex exhaust pipe section to ensure it wont happen again. A new muffler and high flow cat was also installed professionally at the time of the flex pipe. The knocking only started once I received the xj back after the re-welding of the header and installation of the new exhaust components.
Remedies I have already tried:
- New spark plugs
- New spark plug wires
- Premium gas
- Oil is changed every 3,000 miles along with zinc additive
I can't imagine it's a rod or valve knock because I had a remanufactured engine (all new internals) professionally installed about 8 months ago. The only aftermarket product I have on the engine is a cold air intake and a stainless steel header that had already cracked but was rewelded and re-installed along with a flex exhaust pipe section to ensure it wont happen again. A new muffler and high flow cat was also installed professionally at the time of the flex pipe. The knocking only started once I received the xj back after the re-welding of the header and installation of the new exhaust components.
Remedies I have already tried:
- New spark plugs
- New spark plug wires
- Premium gas
- Oil is changed every 3,000 miles along with zinc additive