Changed timing belt know car runs sluggish does not have power in 1st gear, what will cause this?

back firing through the carby is an indication of valve timing, bad valves, ignition timing or crossed HT leads. Check the firing order

some engines bend valves when the belt blows do a compression test

Sure sounds like a slipping transmission to me. When is the last time you changed the transmission fluid? Before you go dumping $2,600 for a new transmission, I'd do a transmission fluid change first. If you do change the fluid, use Dextron 6, it's GM's new transmission fluid, much better than the fluid you have now. Not to scare you, but my transmission went out at about 100k miles, so you're doing good if it hasn't been rebuilt yet.

Hi, It may be in LIMP mode.

What is "limp-home mode" ? This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

Common failures on 4L60E, symptom any possible repair:

Trans shifts into gear harshly, car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmission is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the under-hood fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.

No 1st or 4th available; trans shifts 2nd to 3rd by itself in D or OD and locks the converter :ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

Car goes into gear but feels very sluggish like the brakes are dragging, but it will roll easily (starts out in 4th gear), you manually shift to 2 to get it moving, once it's moving you put it back in OD and the car shifts 3rd to 4th on its own and locks the converter at the appropriate time: ShiftB solenoid failed: Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

Trans seems noisy when moving in 1st and Reverse, noise goes away instantly if you shift to N or the trans goes into 3rd gear: Reaction planetary is worn out due to high miles or insufficient lubrication. Not a critical failure, but not a good sign either. R&R sooner rather than later.

3rd gear starts, can manually shift through all gears. When car has been turned off for a bit, then back on it will run normally.: VSS dropoff w/ Hi-stall converter. The rpms are too high, but VSS is showing no movement. Happens after a tire burning take-off. Doesn't store a code, will not throw a CEL (I've heard that it will store a code if it happens 3 or more times). Cure: Reprogram PCM for VSS dropoff -- PCMforLess knows about it.

If you can get the Jimmy for no more then $500.00 and the engine sounds good and body is good, you may want to invest in the repair of the jimmy. Also note that to have a close look at the fuel line along the frame on the drivers side just by the back doors, the line is know to corroded there on all the SUV's

Have the catalytic converter checked out. It may be worn out inside and causing an exhaust restriction and thus loss of power.

None of what you had done,had any bearing on the problem your having.

You need a clean fuel filter and with that mileage,replace the O2 Sensors every 100,000 miles or less.

Sounds like a transmission issue, have the car scanned for ant transmission related codes. Most transmission shops will check to make sure your transmission is working 100% free of charge. With what you have described, almost sounds like you don't have 1st or 4th gear and your transmission is running on 2nd and 3rd gear. Easy fix if the 1st-4th solenoid needs to be replaced, or the wire harness has gone bad. Start with getting your car scanned and let me know if your transmission is starting on 2nd. Good luck

This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

Trans shifts into gear harshly, car feels sluggish off the line, No 1st, 4th or TCC lockup available, Manual 2nd, 3rd and Reverse are only available gears, CEL is on: Transmission is either in limp-home mode or has lost electrical power. If there are lots of error codes in the PCM, check the under hood fuse that powers the transmission, and if it pops again, look for a short in that circuit like an O2 sensor harness touching exhaust. Otherwise, check PCM codes for a particular fault in the transmission causing the PCM to put it in limp-home mode.

No 1st or 4th available; trans shifts 2nd to 3rd by itself in D or OD and locks the converter : ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

Car goes into gear but feels very sluggish like the brakes are dragging, but it will roll easily (starts out in 4th gear), you manually shift to 2 to get it moving, once it's moving you put it back in OD and the car shifts 3rd to 4th on its own and locks the converter at the appropriate time: ShiftB solenoid failed: Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

IF the abs dash light is on and if the speedometer is sluggish or not working at all, it is probably a bad speed sensor on the transmission. and easy fix under $40 for the part. Mine was stuck in second gear for a while then worked then it stuck in first gear and i had the CHECK ENGINE light on.

Judging from what i know, the timing on the engine is probably a bit off, and i remember reading the exact same problem on another web site and that is also what they said. So just check the timing on the engine or have it checked by a mechanic if you don't know how to do it.

have you changed the fuel filter lately is the check engine light on