Hello,
I've been trying to figure out a problem I have with a '99 4.0l sport 197k miles. It all started with it stumbling and rpm dropping on the highway, lost oil pressure gauge, replaced it drove around town for a while. Getting on the highway I hit the gas hard to merge and it completely fell on its face. No throttle response, no power, could not do over 45mph. stopped at AutoZone got a code for timing. It ran OK at higher rpms. Found the rear 02 sensor wires were rubbing the drive shaft, replaced that.
I still have a rough idle, sometimes 750rpm other 1000rpm. Hesitation and bucking at low speed when going from closed throttle from a stop. The rpm will surge 1 to 2 marks on the tach rapidly, no throttle response. Either I let it continue to give more throttle to get it out of that. Sometimes I hear popping in the exhaust or backfiring.
Since then have done: plugs, wires, cap, rotor, oil change and air filter, tested TPS, Crank PS, Cam PS, cleaned TB and IAC. Had a whistle when letting off the gas on highway, replaced intake and exhaust manifold gaskets and collector gasket. Compression checked OK. Only codes it keeps detecting is P0135, Bank1 Sensor1 voltage high. Replaced front 02. Cleared ECU memory. Checked for vacuum leaks and grounds found nothing.
Only other sensor to replace would be the crank position, Thinking a possible clogged cat, or pulling the trans and changing torque convertor next.
Drained 1/2qt trans fluid out last week. Now at hole level on dipstick. It seemed to shift more firmly than when full. RPM increases before downshifting and it seems to not want to stop or coast without power. Fluid was red but not as clear as new.
When it throws the check engine light it doesn't do the bucking or hesitation on shifting, when I clear it does it again. Wont go 24hrs without getting the 02 code. It only throws the code when shifting into gear after letting idle for a bit when cold.
Any ideas on what I should do next short of pulling the trans or exhaust?
I've been trying to figure out a problem I have with a '99 4.0l sport 197k miles. It all started with it stumbling and rpm dropping on the highway, lost oil pressure gauge, replaced it drove around town for a while. Getting on the highway I hit the gas hard to merge and it completely fell on its face. No throttle response, no power, could not do over 45mph. stopped at AutoZone got a code for timing. It ran OK at higher rpms. Found the rear 02 sensor wires were rubbing the drive shaft, replaced that.
I still have a rough idle, sometimes 750rpm other 1000rpm. Hesitation and bucking at low speed when going from closed throttle from a stop. The rpm will surge 1 to 2 marks on the tach rapidly, no throttle response. Either I let it continue to give more throttle to get it out of that. Sometimes I hear popping in the exhaust or backfiring.
Since then have done: plugs, wires, cap, rotor, oil change and air filter, tested TPS, Crank PS, Cam PS, cleaned TB and IAC. Had a whistle when letting off the gas on highway, replaced intake and exhaust manifold gaskets and collector gasket. Compression checked OK. Only codes it keeps detecting is P0135, Bank1 Sensor1 voltage high. Replaced front 02. Cleared ECU memory. Checked for vacuum leaks and grounds found nothing.
Only other sensor to replace would be the crank position, Thinking a possible clogged cat, or pulling the trans and changing torque convertor next.
Drained 1/2qt trans fluid out last week. Now at hole level on dipstick. It seemed to shift more firmly than when full. RPM increases before downshifting and it seems to not want to stop or coast without power. Fluid was red but not as clear as new.
When it throws the check engine light it doesn't do the bucking or hesitation on shifting, when I clear it does it again. Wont go 24hrs without getting the 02 code. It only throws the code when shifting into gear after letting idle for a bit when cold.
Any ideas on what I should do next short of pulling the trans or exhaust?
